Вы можете столкнуться с ошибкой SQL Server 18456, если сервер не может аутентифицировать соединение, и это может быть вызвано недоступностью прав администратора для SQL-сервера или если протокол TCP / IP отключен в настройках SQL-сервера.
Проблема возникает, когда пользователь пытается подключиться к серверу SQL (локальному или удаленному), но обнаруживает ошибку 18456 (с разными состояниями).
Ошибка Microsoft SQL Server 18456
Вы можете исправить ошибку SQL-сервера 18456, попробовав приведенные ниже решения, но перед этим проверьте, решает ли проблему перезагрузка сервера, клиентского компьютера и сетевых компьютеров. Кроме того, убедитесь, что вы вводите правильное имя пользователя и пароль (а не копируете адрес).
Также проверьте, правильно ли вы вводите имя базы данных (без опечаток), и убедитесь, что вы соответствующим образом обновили файл конфигурации. Кроме того, проверьте, решает ли проблему разблокировка учетной записи (с помощью запроса ALTER LOGIN WITH PASSWORD = UNLOCK). Если вы видите ошибки в журнале ошибок SQL, убедитесь, что ваш SQL-сервер не атакован. И последнее, но не менее важное: убедитесь, что часы сервера и клиентского компьютера установлены правильно.
Вы можете столкнуться с ошибкой 18456, если SQL-сервер не имеет повышенных разрешений на выполнение своей операции, и запуск его от имени администратора (или отключение элементов управления UAC на сервере) может решить проблему.
Откройте SQL Server от имени администратора
- Щелкните Windows и введите SQL Server Management Studio.
- Теперь щелкните правой кнопкой мыши SMSS и выберите «Запуск от имени администратора».
Запустите Microsoft SQL Server Management Studio от имени администратора.
- Затем нажмите Да (если получено приглашение UAC) и проверьте, не содержит ли SQL-сервер ошибки 18456.
- Если нет, проверьте, решает ли проблему отключение UAC на сервере.
Запуск SQL Server в однопользовательском режиме
- Щелкните Windows, введите и откройте диспетчер конфигурации SQL Server.
- Теперь щелкните правой кнопкой мыши службу SQL Server (на вкладке «Службы SQL Server») и выберите «Свойства».
Откройте свойства SQL Server
- Затем перейдите на вкладку Параметры запуска и в поле Укажите параметр запуска введите: -m
- Теперь нажмите «Добавить» и примените изменения.
Добавьте параметр «-m» к параметрам запуска SQL Server.
- Затем щелкните правой кнопкой мыши службу SQL Server и выберите «Перезагрузить».
Перезапустите службу SQL Server.
- Теперь щелкните Windows, введите: SQL Server Management Studio, щелкните правой кнопкой мыши SMSS и выберите Запуск от имени администратора.
- Теперь проверьте, можете ли вы подключиться к SQL Server от имени администратора.
- Если это так, добавьте учетную запись домена на SQL-сервер и назначьте ей роль SysAdmin.
- Теперь вернитесь в окно диспетчера конфигурации SQL Server и удалите параметр -m на вкладке Параметры запуска.
- Затем перезапустите службу SQL Server (шаг 3) и проверьте, нормально ли работает SQL-сервер.
Если проблема не исчезнет, проверьте, правильно ли настроены параметры запуска или сведения о пути. Если проблема все еще существует, убедитесь, что ваша учетная запись пользователя имеет необходимые разрешения для служб базы данных / отчетов, а затем проверьте, решена ли проблема.
Включите протокол TCP / IP в диспетчере конфигурации сервера.
Код ошибки 18456 на сервере SQL означает, что серверу не удалось аутентифицировать соединение, и это может произойти, если протокол TCP / IP, необходимый для доступа к базе данных в сети, отключен в диспетчере конфигурации сервера. В этом контексте включение TCP / IP в диспетчере конфигурации SQL Server может решить проблему.
- Щелкните Windows и разверните Microsoft SQL Server, указав год, например, 2008 (вам может потребоваться немного прокрутить, чтобы найти параметр).
- Теперь откройте диспетчер конфигурации SQL Server и нажмите Да (если получено приглашение UAC).
- Затем разверните сетевую конфигурацию SQL Server и выберите Протоколы для (имя сервера / базы данных) на левой панели.
- Теперь на правой панели дважды щелкните TCP / IP и выберите Да в раскрывающемся списке Включено.
Откройте TCP / IP в протоколах конфигурации сети SQL Server
- Затем примените изменения и щелкните Windows.
Включить TCP / IP в SQL
- Теперь введите «Службы», щелкните правой кнопкой мыши результат «Службы» и выберите «Запуск от имени администратора».
Откройте службы в качестве администратора
- Затем щелкните правой кнопкой мыши SQL Server (с именем сервера) и выберите «Перезагрузить».
Перезапустите службу SQL в окне служб.
- Теперь проверьте, очищен ли SQL-сервер от ошибки 18456.
Если это не помогло, убедитесь, что вы подключаетесь к правильному порту SQL-сервера (особенно, если вы используете сервер в многосерверной среде).
Измените режим аутентификации SQL Server
Сервер SQL может отображать ошибку 18456, если метод аутентификации сервера SQL не настроен должным образом (например: вы пытаетесь войти в систему с использованием аутентификации сервера SQL, тогда как сервер настроен на использование аутентификации Windows). В этом случае изменение метода аутентификации SQL-сервера может решить проблему. Прежде чем двигаться дальше, убедитесь, что для текущего пользователя включен статус входа в систему (например, SA).
- В обозревателе объектов Microsoft SQL Server Management Studio щелкните правой кнопкой мыши свой сервер и выберите «Свойства».
- Теперь на левой панели выберите Безопасность, а на правой панели выберите SQL Server и проверку подлинности Windows (или наоборот).
Включить SQL Server и проверку подлинности Windows
- Затем примените изменения и в обозревателе объектов щелкните правой кнопкой мыши сервер.
- Теперь выберите «Перезагрузить» и после перезапуска проверьте, можете ли вы подключиться к базе данных без ошибки 18456.
Если вы не можете войти в SQL, вы можете установить MS Power Tools и выполнить следующую команду с повышенными привилегиями:
psexec.exe -i -s ssms.exe
После этого вы можете использовать учетную запись установки SQL, чтобы внести изменения, а также убедиться, что учетная запись SA не отключена:
Включите учетную запись SA и сбросьте пароль учетной записи
Если вы не можете подключиться к SQL Server, то включение учетной записи SA SQL-сервера и сброс его пароля может решить проблему.
- Запустите Microsoft SQL Server Management Studio (возможно, вам придется использовать учетную запись администратора домена) и разверните Безопасность.
- Затем дважды щелкните Logins и откройте SA.
Откройте учетную запись SA в Microsoft SQL Server Management Studio.
- Теперь введите новый пароль и подтвердите его (убедитесь, что вы используете надежный пароль).
- Затем перейдите на вкладку Server Roles и убедитесь, что выбраны следующие роли: Public Sysadmin
Включение ролей общедоступного сервера и сервера системного администратора для учетной записи SA
- Теперь перейдите на вкладку «Статус» и на правой панели выберите «Включено» (в разделе «Вход»).
Включение учетной записи SA в SQL
- Затем примените изменения и нажмите кнопку Windows.
- Теперь введите Services и щелкните его правой кнопкой мыши.
- Затем выберите «Запуск от имени администратора» и перейдите к службе SQL Server.
- Теперь щелкните его правой кнопкой мыши и выберите «Перезагрузить».
- После перезапуска службы проверьте, устранена ли ошибка 18456 SQL-сервера.
Создайте новый логин и перезапустите службы Reporting Services
Если вы не можете использовать какую-либо учетную запись для подключения к базе данных, то создание новой учетной записи и перезапуск служб отчетов может решить проблему.
- Запустите Microsoft SQL Server Management Studio и разверните вкладку «Безопасность».
- Затем разверните Логины и щелкните его правой кнопкой мыши.
- Теперь выберите «Новый вход» и введите учетные данные (в имени входа выберите учетную запись компьютера), если используется проверка подлинности SQL Server.
Создать новый логин в SQL Server
- Затем не забудьте снять флажок «Пользователь должен сменить пароль при следующем входе в систему» и выберите базу данных.
- Теперь перейдите на вкладку Server Roles и выберите роль Public.
- Затем на вкладке «Сопоставление пользователей» обязательно выберите базу данных и выберите db_owner.
Выберите db_owner для базы данных в SQL
- Теперь примените ваши изменения и щелкните Windows.
- Затем введите Services и щелкните правой кнопкой мыши результат Services. Затем выберите Запуск от имени администратора.
- Теперь щелкните правой кнопкой мыши службу отчетов SQL Server и выберите «Перезагрузить».
Перезапустите службу отчетов SQL Server.
- Затем повторно подключитесь к базе данных и проверьте, очищен ли сервер SQL от ошибки 18456.
Если это так, убедитесь, что вы создали пользователя в BUILTIN administrators, и затем вы можете использовать этого пользователя для управления SQL Server. Если вы восстановили базу данных из резервной копии, будет лучше удалить и повторно добавить пользователей, чтобы удалить все старые записи пользователей. Если вы хотите запустить SQL-сервер от имени другого пользователя, введите Microsoft SQL Server в поиске Windows, Shift + щелкните правой кнопкой мыши на SQL Server и выберите «Запуск от имени другого пользователя». И последнее, но не менее важное: проверьте, решает ли проблема использование Azure Data Studio с сервером SQL.
By default login failed error message is nothing but a client user connection has been refused by the server due to mismatch of login credentials. First task you might check is to see whether that user has relevant privileges on that SQL Server instance and relevant database too, thats good. Obviously if the necessary prvileges are not been set then you need to fix that issue by granting relevant privileges for that user login.
Althought if that user has relevant grants on database & server if the Server encounters any credential issues for that login then it will prevent in granting the authentication back to SQL Server, the client will get the following error message:
Msg 18456, Level 14, State 1, Server <ServerName>, Line 1
Login failed for user '<Name>'
Ok now what, by looking at the error message you feel like this is non-descriptive to understand the Level & state. By default the Operating System error will show ‘State’ as 1 regardless of nature of the issues in authenticating the login. So to investigate further you need to look at relevant SQL Server instance error log too for more information on Severity & state of this error. You might look into a corresponding entry in log as:
2007-05-17 00:12:00.34 Logon Error: 18456, Severity: 14, State: 8.
or
2007-05-17 00:12:00.34 Logon Login failed for user '<user name>'.
As defined above the Severity & State columns on the error are key to find the accurate reflection for the source of the problem. On the above error number 8 for state indicates authentication failure due to password mismatch. Books online refers: By default, user-defined messages of severity lower than 19 are not sent to the Microsoft Windows application log when they occur. User-defined messages of severity lower than 19 therefore do not trigger SQL Server Agent alerts.
Sung Lee, Program Manager in SQL Server Protocols (Dev.team) has outlined further information on Error state description:The common error states and their descriptions are provided in the following table:
ERROR STATE ERROR DESCRIPTION
------------------------------------------------------------------------------
2 and 5 Invalid userid
6 Attempt to use a Windows login name with SQL Authentication
7 Login disabled and password mismatch
8 Password mismatch
9 Invalid password
11 and 12 Valid login but server access failure
13 SQL Server service paused
18 Change password required
Well I'm not finished yet, what would you do in case of error:
2007-05-17 00:12:00.34 Logon Login failed for user '<user name>'.
You can see there is no severity or state level defined from that SQL Server instance’s error log. So the next troubleshooting option is to look at the Event Viewer’s security log [edit because screen shot is missing but you get the
idea, look in the event log for interesting events].
Just happened to me, and turned out to be different than all other cases listed here.
I happen to have two virtual servers hosted in the same cluster, each with it own IP address. The host configured one of the servers to be the SQL Server, and the other to be the Web server. However, SQL Server is installed and running on both. The host forgot to mention which of the servers is the SQL and which is the Web, so I just assumed the first is Web, second is SQL.
When I connected to the (what I thought is) SQL Server and tried to connect via SSMS, choosing Windows Authentication, I got the error mentioned in this question. After pulling lots of hairs, I went over all the setting, including SQL Server Network Configuration, Protocols for MSSQLSERVER:
Double clicking the TCP/IP gave me this:
The IP address was of the other virtual server! This finally made me realize I simply confused between the servers, and all worked well on the second server.
| title | description | author | ms.author | ms.reviewer | ms.date | ms.service | ms.subservice | ms.topic | helpviewer_keywords |
|---|---|---|---|---|---|---|---|---|---|
|
MSSQLSERVER_18456 |
A connection attempt is rejected due to a failure with a bad password or username in SQL Server. See an explanation of the error and possible resolutions. |
MashaMSFT |
mathoma |
jopilov, randolphwest |
01/16/2023 |
sql |
supportability |
reference |
18456 (Database Engine error) |
MSSQLSERVER_18456
[!INCLUDE SQL Server]
Details
| Attribute | Value |
|---|---|
| Product Name | SQL Server |
| Event ID | 18456 |
| Event Source | MSSQLSERVER |
| Component | SQLEngine |
| Symbolic Name | LOGON_FAILED |
| Message Text | Login failed for user ‘%.*ls’.%.*ls |
Explanation
You get this error message when a connection attempt is rejected because of an authentication failure. User logins can fail for many reasons, such as invalid credentials, password expiration, and enabling the wrong authentication mode. In many cases, error codes include descriptions.
User action
The following examples are some of the common login failures. Select the exact error that you’re experiencing to troubleshoot the issue:
-
Login failed for user ‘<username>’ or login failed for user ‘<domain><username>’
-
Login failed for user ‘NT AUTHORITYANONYMOUS’ LOGON
-
Login failed for user ’empty’
-
Login failed for user ‘(null)’
Login failed for user ‘<username>’ or login failed for user ‘<domain><username>’
If the domain name isn’t specified, the problem is a failing SQL Server login attempt. If the domain name is specified, the problem is a failing Windows user account login. For potential causes and suggested resolutions, see:
| Potential cause | Suggested resolution |
|---|---|
| You’re trying to use SQL Server Authentication, but the SQL server instance is configured for Windows Authentication mode. | Verify that SQL Server is configured to use SQL Server and Windows Authentication mode. You can review and change the authentication mode for your SQL Server instance on the Security page under Properties for the corresponding instance in SQL Server Management Studio (SSMS). For more information, see Change server authentication mode. Alternatively, you can change your application to use Windows Authentication mode to connect to SQL Server. Note: You can see a message like the following one in the SQL Server Error log for this scenario: Login failed for user '<UserName>'. Reason: An attempt to login using SQL authentication failed. Server is configured for Windows authentication only. |
| Login doesn’t exist on the SQL Server instance you’re trying to connect to. | Verify that the SQL Server login exists and that you’ve spelled it properly. If the login doesn’t exist, create it. If it’s present but misspelled, correct that in the application connection string. The SQL Server Errorlog will have one of the following messages: — Login failed for user 'username'. Reason: Could not find a login matching the name provided.— Login failed for user 'Domainusername'. Reason: Could not find a login matching the name provided.This can be a common issue if you deploy an application that uses a DEV or QA server into production and you fail to update the connection string. To resolve this issue, validate that you are connecting to the appropriate server. If not, correct the connection string. If it is, grant the login access to your SQL Server. Or if it’s a windows login grant access directly or add it to a local or domain group that is allowed to connect to the database server. For more information, see Create a Login. |
| You’re using SQL Server Authentication, but the password you specified for SQL Server login is incorrect. | Check the SQL error log for messages like «Reason: Password did not match that for the login provided» to confirm the cause. To fix the issue, use the correct password in your application or use a different account if you can’t remember the password. Alternatively, work with your SQL Server administrator to reset the password for the account. If the application is SQL Server Integration Services (SSIS), there may be multiple levels of a Configuration file for the job, which may override the Connection Manager settings for the package. If the application was written by your company and the connection string is programmatically generated, engage the development team to resolve the issue. As a temporary workaround, hard-code the connection string and test. Use a UDL file or a script to prove a connection is possible with a hard-coded connection string. |
| Server name is incorrect. | Ensure you’re connecting to the correct server. |
| You’re trying to connect using Windows authentication but are logged into an incorrect domain. | Verify that you’re properly logged into the correct domain. The error message usually displays the domain name. |
| You aren’t running your application (for example, SSMS) as an administrator. | If you’re trying to connect using your administrator credentials, start your application by using the Run as Administrator option. When connected, add your Windows user as an individual login. |
| Login is deleted after a migration to a contained database user. | If the Database Engine supports contained databases, confirm that the login wasn’t deleted after migration to a contained database user. For more information, see Contained Database Authentication: Introduction. |
| Login’s default database is offline or otherwise not available. | Check with your SQL Server administrator and resolve issues related to database availability. If the login has permissions to other databases on the server and you don’t need to access the currently configured default database in your application, use one of the following options: — Request the administrator to change the default database for the login using ALTER LOGIN statement or SSMS. — Explicitly specify a different database in your application connection string. Or if you’re using SSMS switch to the Connection Properties tab to specify a database that is currently available.Applications like SSMS may show an error message like the following one: Cannot open user default database. Login failed.Login failed for user <user name>. (Microsoft SQL Server, Error: 4064)SQL Server Errorlog will have an error message like the following one: Login failed for user '<user name>'. Reason: Failed to open the database '<dbname>' specified in the login properties [CLIENT: <ip address>]For more information, see MSSQLSERVER_4064. |
| The database explicitly specified in the connection string or in SSMS is incorrectly spelled, offline, or otherwise not available. | — Fix the database name in the connection string. Pay attention to case sensitivity if using a case sensitive collation on the server. — If the database name is correct, check with your SQL Server administrator and resolve issues related to database availability. Check if the database is offline, not recovered, and so on. — If the login has been mapped to users with permissions to other databases on the server and you don’t need to access the currently configured database in your application, then specify a different database in your connection string. Or if you’re connecting with SSMS, use the Connection Properties tab to specify a database that is currently available. SQL Server Errorlog will have an error message like the following one: Login failed for user <UserName>. Reason: Failed to open the explicitly specified database 'dbname'. [CLIENT: <ip address>]Note: If the login’s default database is available, SQL Server allows the connection to succeed. For more information, see MSSQLSERVER_4064. |
| The user doesn’t have permissions to the requested database. | — Try connecting as another user that has sysadmin rights to see if connectivity can be established. — Grant the login access to the database by creating the corresponding user (for example, CREATE USER [<UserName>] FOR LOGIN [UserName]) |
Also, check the extensive list of error codes at Troubleshooting Error 18456.
For more troubleshooting help, see Troubleshooting SQL Client / Server Connectivity Issues.
Login failed for user NT AUTHORITYANONYMOUS LOGON
There are at least four scenarios for this issue. In the following table, examine each applicable potential cause, and use the appropriate resolution:
See the note below the table for an explanation of the term double hop.
| Potential causes | Suggested resolutions |
|---|---|
| You’re trying to pass NT LAN Manager (NTLM) credentials from one service to another service on the same computer (for example: from IIS to SQL server), but a failure occurs in the process. | Add the DisableLoopbackCheck or BackConnectionHostNames registry entries. |
| There are double-hop (constraint delegation) scenarios across multiple computers. The error could occur if the Kerberos connection fails because of Service Principal Names (SPN) issues. | Run SQLCheck on each SQL Server and the web server. Use the troubleshooting guides: 0600 Credential Delegation Issue and 0650 SQL Server Linked Server Delegation Issues. |
| If no double-hop (constraint delegation) is involved, then likely duplicate SPNs exist, and the client is running as a LocalSystem or another machine account that gets NTLM credentials instead of Kerberos credentials. | Use SQLCheck or Setspn.exe to diagnose and fix any SPN-related issues. Also review Overview of the Kerberos Configuration Manager for SQL Server. |
| Windows Local Security policy may have been configured to prevent the use of the machine account for remote authentication requests. | Navigate to Local Security Policy > Local Policies > Security Options > Network security: Allow Local System to use computer identity for NTLM, select the Enabled option if the setting is disabled, and then select OK. Note: As detailed on the Explain tab, this policy is enabled in Windows 7 and later versions by default. |
| Intermittent occurrence of this issue when using constrained delegation can indicate presence of an expired ticket that can’t be renewed by middle tier. This is an expected behavior with either linked server scenario or any application that is holding a logon session for more than 10 hours. | Change delegation settings on your middle-tier server from Trust this computer for delegation to specified services only – Use Kerberos Only to Trust this computer for delegation to specified services only — Use any protocol. For more information review Intermittent ANONYMOUS LOGON of SQL Server linked server double hop. |
[!NOTE]
A double-hop typically involves delegation of user credentials across multiple remote computers. For example, assume you have a SQL Server instance named SQL1 where you created a linked server for a remote SQL Server named SQL2. In linked server security configuration, you selected the option Be made using the login’s current security context. When using this configuration, if you execute a linked server query on SQL1 from a remote client computer named Client1, the windows credentials will first have to hop from Client1 to SQL1 and then from SQL1 to SQL2 (hence, it’s called a double-hop). For more information, see Understanding Kerberos Double Hop and Kerberos Constrained Delegation Overview
Login failed for user (empty)
This error occurs when a user tries unsuccessfully to log in. This error might occur if your computer isn’t connected to the network. For example, you may receive an error message that resembles the following one:
Source: NETLOGON
Date: 8/12/2012 8:22:16 PM
Event ID: 5719
Task Category: None
Level: Error
Keywords: Classic
User: N/A
Computer: <computer name>
Description: This computer was not able to set up a secure session with a domain controller in domain due to the following: The remote procedure call was cancelled.
This may lead to authentication problems. Make sure that this computer is connected to the network. If the problem persists, please contact your domain administrator.
An empty string means that SQL Server tried to hand off the credentials to the Local Security Authority Subsystem Service (LSASS) but couldn’t because of some problem. Either LSASS wasn’t available, or the domain controller couldn’t be contacted.
Check the event logs on the client and the server for any network-related or Active Directory-related messages that were logged around the time of the failure. If you find any, work with your domain administrator to fix the issues.
Login failed for user ‘(null)’
An indication of «null» could mean that LSASS can’t decrypt the security token by using the SQL Server service account credentials. The main reason for this condition is that the SPN is associated with the wrong account.
To fix the issue, follow these steps:
-
Use the SQLCheck or Setspn.exe to diagnose and fix SPN-related issues.
-
Use SQLCheck to check whether the SQL Service account is trusted for delegation. If the output indicates that the account isn’t trusted for delegation, work with your Active Directory administrator to enable delegation for the account.
-
Diagnose and fix Domain Name System (DNS) name resolution issues. For example:
-
Ping IP address by using PowerShell scripts:
ping -a <your_target_machine>(use-4for IPv4 and-6IPv6 specifically)ping -a <your_remote_IPAddress>
-
Use NSLookup to enter your local and remote computer name and IP address multiple times.
-
-
Look for any discrepancies and mismatches in the returned results. The accuracy of the DNS configuration on the network is important for a successful SQL Server connection. An incorrect DNS entry could cause numerous connectivity issues later.
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Make sure that firewalls or other network devices don’t block a client from connecting to the domain controller. SPNs are stored in Active Directory. If the clients can’t communicate with the directory, the connection can’t succeed.
Additional error information
To increase security, the error message that is returned to the client deliberately hides the nature of the authentication error. However, in the [!INCLUDEssNoVersion] error log, a corresponding error contains an error state that maps to an authentication failure condition. Compare the error state to the following list to determine the reason for the login failure.
| State | Description |
|---|---|
| 1 | Error information isn’t available. This state usually means you don’t have permission to receive the error details. Contact your [!INCLUDEssNoVersion] administrator for more information. |
| 2 | User ID isn’t valid. |
| 5 | User ID isn’t valid. |
| 6 | An attempt was made to use a Windows login name with SQL Server Authentication. |
| 7 | Login is disabled, and the password is incorrect. |
| 8 | The password is incorrect. |
| 9 | Password isn’t valid. |
| 11 | Login is valid, but server access failed. One possible cause of this error is when the Windows user has access to [!INCLUDEssNoVersion] as a member of the local administrators’ group, but Windows isn’t providing administrator credentials. To connect, start the connecting program using the Run as administrator option, and then add the Windows user to [!INCLUDEssNoVersion] as a specific login. |
| 12 | Login is valid login, but server access failed. |
| 18 | Password must be changed. |
| 38, 46 | Couldn’t find database requested by user. |
| 58 | When SQL Server is set to use Windows Authentication only, and a client attempts to log in using SQL authentication. Another cause is when SIDs don’t match. |
| 102 — 111 | Azure AD failure. |
| 122 — 124 | Failure due to empty user name or password. |
| 126 | Database requested by user doesn’t exist. |
| 132 — 133 | Azure AD failure. |
Other error states exist and signify an unexpected internal processing error.
More rare possible cause
The error reason An attempt to login using SQL authentication failed. Server is configured for Windows authentication only. can be returned in the following situations.
-
When the server is configured for mixed mode authentication, and an ODBC connection uses the TCP protocol, and the connection doesn’t explicitly specify that the connection should use a trusted connection.
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When SQL server is configured for mixed mode authentication, and an ODBC connection uses named pipes, and the credentials the client used to open the named pipe are used to automatically impersonate the user, and the connection string doesn’t explicitly specify the use of a trusted authentication.
To resolve this issue, include TRUSTED_CONNECTION = TRUE in the connection string.
Examples
In this example, the authentication error state is 8. This indicates that the password is incorrect.
| Date | Source | Message |
|---|---|---|
| 2007-12-05 20:12:56.34 | Logon | Error: 18456, Severity: 14, State: 8. |
| 2007-12-05 20:12:56.34 | Logon | Login failed for user ‘<user_name>’. [CLIENT: <ip address>] |
[!NOTE]
When [!INCLUDEssNoVersion] is installed using Windows Authentication mode and is later changed to [!INCLUDEssNoVersion] and Windows Authentication mode, the sa login is initially disabled. This causes the state 7 error: «Login failed for user ‘sa’.» To enable the sa login, see Change Server Authentication Mode.
See also
- 0420 Reasons for Consistent Auth Issues
Updated in July 2020 with a few new states.
I think we’ve all dealt with error 18456, whether it be an application unable to access SQL Server, credentials changing over time, or a user who can’t type a password correctly.
The trick to troubleshooting this error number is that the error message returned to the client or application trying to connect is intentionally vague – the error message is similar for most errors, and the state is always 1. In a few cases, some additional information is included, but for the most part several of these conditions appear the same to the end user. The reason for this is to be careful not to disclose too much information to a would-be attacker.
But this makes troubleshooting hard.
In order to figure out what is really going wrong, you need to have alternative access to the SQL Server and inspect the log for the true state in the error message. I helped our support team just today solve a client’s 18456 issues – once we tracked down the error log and saw that it was state 16, it was easy to determine that their login had been set up with a default database that had been detached long ago.
When I see folks struggling with this problem, I almost always see them pointed to this old MSDN blog post (or this other version from MSDN), which has a very brief partial list and a lot of unanswered questions. A newer list appears here, with some useful info, but it is still incomplete.
So here is what I consider a more complete listing of all the various states for login failures. I included an instance of 18470 under state 1 for completeness.
| State | Example / Description (note: the verbose message usually has [CLIENT: <IP>] suffix) |
|---|---|
| 1 |
Error: 18470, Severity: 14, State: 1. Login failed for user ‘<x>’. Reason: The account is disabled. |
| State 1 now occurs when a login is disabled – but actually, the error in the log is 18470, not 18456 – because the login is disabled, it doesn’t get that far. See state 7.Prior to SQL Server 2005, State 1 always appeared in the log for all login failures, making for fun troubleshooting. 🙂 | |
| 2 |
Error: 18456, Severity: 14, State: 2. Login failed for user ‘<x>’. Reason: Could not find a login matching the name provided. |
| The login (whether using SQL or Windows Authentication) does not exist. For Windows Auth, it likely means that the login hasn’t explicitly been given access to SQL Server – which may mean it is not a member of an appropriate domain group. It could also mean that you’ve created a server-level login, mapped a database user with a different name to that login, and are trying to connect using the user name, not the login name. This is the same as State 5, but State 2 indicates that the login attempt came from a remote machine. | |
| 5 |
Error: 18456, Severity: 14, State: 5. Login failed for user ‘<x>’. Reason: Could not find a login matching the name provided. |
| Like state 2, the login does not exist in SQL Server, but the login attempt came from the local machine. For both state 2 and 5, prior to SQL Server 2008, the reason was not included in the error log – just the login failed message. And starting in Denali, for both state 2 and 5, this error can happen if you specify the correct username and password for a contained database user, but the wrong (or no) database. Note that if you are trying to connect to a contained database using the connection dialog in SSMS, and you try to <Browse server…> for the database instead of typing the name explicitly, you will first receive a prompt «Browsing the available databases on the server requires connecting to the server. This may take a few moments. Would you like to continue?» If the SQL auth credentials do not also match a login at the server level, you will then receive an error message, because your contained user does not have access to master.sys.databases. The error message in the UI is, «Failed to connect to server <server>. (Microsoft.SqlServer.ConnectionInfo)Login failed for user ‘<x>’. (Microsoft SQL Server, Error: 18456).» The takeaway here: always specify the database name explicitly in the options tab of the connection dialog; do not use the browse feature. | |
| 6 |
Error: 18456, Severity: 14, State: 6. Login failed for user ‘<xy>’. Reason: Attempting to use an NT account name with SQL Server Authentication. |
| This means you tried to specify SQL authentication but entered a Windows-style login in the form of DomainUsername. Make sure you choose Windows Authentication (and you shouldn’t have to enter your domain / username when using Win Auth unless you are using runas /netonly to launch Management Studio). In SQL Server 2012 at least, you will only get state 6 if the domainusername format matches an actual domain and username that SQL Server recognizes. If the domain is invalid or if the username isn’t an actual Windows account in that domain, it will revert to state 5 (for local attempts) or state 2 (for remote attempts), since the login doesn’t exist. | |
| 7 |
Error: 18456, Severity: 14, State: 7. Login failed for user ‘<x>’. Reason: An error occurred while evaluating the password. |
| The login is disabled *and* the password is incorrect. This shows that password validation occurs first, since if the password is correct and the login is disabled, you get error 18470 (see state 1 above). It’s possible that your application is sending cached credentials and the password has been changed or reset in the meantime – you may try logging out and logging back in to refresh these credentials. | |
| 8 |
Error: 18456, Severity: 14, State: 8. Login failed for user ‘<x>’. Reason: Password did not match that for the login provided. |
|
Probably the simplest of all: the password is incorrect (cASe sEnsiTiVitY catches a lot of folks here). Note that it will say «the login provided» even if you attempted to connect as a contained database user but forgot to specify a database, specified the wrong database, or typed the password incorrectly – unless it finds a match, SQL Server doesn’t have any idea you were attempting to use a contained database user. An interesting case here is Docker containers – |
|
| 9 |
Error: 18456, Severity: 14, State: 9. Login failed for user ‘<xy>’. |
| Like state 2, I have not seen this in the wild. It allegedly means that the password violated a password policy check, but I tried creating a login conforming to a weak password policy, strengthened the policy, and I could still log in fine. And obviously you can’t create a login with, or later set, a password that doesn’t meet the policy. Let me know if you’ve seen it. | |
| 10 |
Error: 18456, Severity: 14, State: 10. Login failed for user ‘<x>’. |
| This is a rather complicated variation on state 9; as KB #925744 states, this means that password checking could not be performed because the login is disabled or locked on the domain controller (note that if SQL Server does not start, it could be because the account that is locked or disabled is the SQL Server service account). No reason or additional information is provided in the «verbose» message in the error log. | |
| 11 12 |
Error: 18456, Severity: 14, State: 11. Login failed for user ‘<x>’. Reason: Login-based server access validation failed with an infrastructure error. Check for previous errors. Error: 18456, Severity: 14, State: 12. |
| States 11 and 12 mean that SQL Server was able to authenticate you, but weren’t able to validate with the underlying Windows permissions. It could be that the Windows login has no profile or that permissions could not be checked due to UAC. Try running SSMS as administrator and/or disabling UAC. Another reason could be that the domain controller could not be reached. You may need to resort to re-creating the login (see this post from Simon Sabin). Finally, PSS has recently released more information about states 11 and 12; see this post for potential scenarios and solutions, and also see states 146-149 below for changes in SQL Server 2016. | |
| 13 |
Error: 18456, Severity: 14, State: 13. Login failed for user ‘<x>’. Reason: SQL Server service is paused. No new connections can be accepted at this time. |
| This state occurs when the SQL Server service has been paused (which you can do easily and even accidentally from the context menu in Object Explorer). | |
| 16 |
Error: 18456, Severity: 14, State: 16. Login failed for user ‘<x>’. You may also see: A connection was successfully established with the server, but then an error occurred during the pre-login handshake. |
| State 16, which only occurs prior to SQL Server 2008, means that the default database was inaccessible. This could be because the database has been removed, renamed, or is offline (it may be set to AutoClose). This state does not indicate a reason in the error log. In 2008 and beyond, this is reported as state 40 (see below), with a reason. In SQL Server 2005, this state may also be reported if the user’s default database is online but the database they explicitly requested is not available for the reasons stated above (also see state 27). If you get the pre-login handshake message, it may be because you’ve disabled SSL on the server. | |
| 18 |
Error: 18456, Severity: 14, State: 18. Login failed for user ‘<x>’. |
| Supposedly this indicates that the user needs to change their password. In SQL Server 2005, 2008 R2 and SQL Server 2012, I found this was raised as error 18488, not 18456; this is because for SQL logins the change password dialog just delays logging in, and is not actually a login failure. I suspect that, like state 16, this state will no longer appear in future versions of SQL Server. | |
| 23 |
Error: 18456, Severity: 14, State: 23. Login failed for user ‘<x>’. Reason: Access to server validation failed while revalidating the login on the connection. |
| There could be a few reasons for state 23. The most common one is that connections are being attempted while the service is being shut down. However if this error occurs and it is not surrounded in the log by messages about SQL Server shutting down, and there is no companion reason along with the message, I would look at KB #937745, which implies that this could be the result of an overloaded server that can’t service any additional logins because of connection pooling issues. Finally, if there *is* a companion reason, it may be the message indicated to the right, indicating that SQL Server was running as a valid domain account and, upon restarting, it can’t validate the account because the domain controller is offline or the account is locked or no longer valid. Try changing the service account to LocalSystem until you can sort out the domain issues. | |
| 27 |
Error: 18456, Severity: 14, State: 27. Login failed for user ‘<x>’. |
| State 27, like state 16, only occurs prior to SQL Server 2008. It means that the database specified in the connection string has been removed, renamed, or is offline (possibly due to AutoClose) – though in every case I tried, it was reported as state 16. This state does not indicate a reason in the error log. In 2008 and onward this is reported as state 38 (see below), with a reason. | |
| 28 |
Error: 18456, Severity: 14, State: 28. Login failed for user ‘<x>’. |
| I have not experienced this issue but I suspect it involves overloaded connection pooling and connection resets. I think you will only see state 28 prior to SQL Server 2008. | |
| 38 |
Error: 18456, Severity: 14, State: 38. Login failed for user ‘<x>’. Reason: Failed to open the database specified in the login properties. or Reason: Cannot open database «<database>» requested by the login. The login failed. |
|
The database specified in the connection string, or selected in the Options > Connection Properties tab of the SSMS connection dialog, is no longer valid or online (it might be set to AutoClose or the user may simply not have permission). I came across this once when I typed <default> here instead of picking that option from the list. This is reported as state 27 or state 16 prior to SQL Server 2008.
Note that this could also be a symptom of an orphaned login. After establishing mirroring, Availability Groups, log shipping, etc. you may have created a new login or associated a user with a login on the primary database. The database-level user information gets replayed on the secondary servers, but the login information does not. Everything will work fine – until you have a failover. In this situation, you will need to synchronize the login and user information (for one example, see this script from the late Robert Davis). |
|
| 40 |
Error: 18456, Severity: 14, State: 40. Login failed for user ‘<x>’. Reason: Failed to open the explicitly specified database. |
| Usually this means the login’s default database is offline (perhaps due to AutoClose) or no longer exists. Resolve by fixing the missing database, or changing the login’s default database using ALTER LOGIN (for older versions, use sp_defaultdb, which is now deprecated). This is reported as state 16 prior to SQL Server 2008. | |
| 46 |
Error: 18456, Severity: 14, State: 46. Login failed for user ‘<x>’. Reason: Failed to open the database configured in the login object while revalidating the login on the connection. |
| State 46 may occur when the login (or login mapping to the service account) does not have a valid database selected as their default database. (I am guessing here but I think this may occur when the login in question is attempting to perform log shipping. Again, just a guess based on the few conversations I discovered online.) It can also occur if the classifier function (Resource Governor) or a logon trigger refers to a database that is offline, no longer exists, or is set to AutoClose. | |
| 50 |
Error: 18456, Severity: 14, State: 50. Login failed for user ‘<x>’. Reason: Current collation did not match the database’s collation during connection reset. |
| As the message implies, this can occur if the default collation for the login is incompatible with the collation of their default database (or the database explicitly specified in the connection string). It can also happen if they are using a client tool like Management Studio which may, when they have been disconnected, try to connect to master upon reconnection instead of their default database. | |
| 51 |
Error: 18456, Severity: 14, State: 51. Login failed for user ‘<x>’. Reason: Failed to send an environment change notification to a log shipping partner node while revalidating the login. |
| Like states 11 & 12, this could have to do with UAC, or that the domain controller could not be reached, or that the domain account could not authenticate against the log shipping partner, or that the log shipping partner was down. Try changing the service account for SQL Server to a known domain or local account, rather than the built-in local service accounts, and validating that the partner instance is accessible, as well as the database that is being requested in the connection string and the default database of the login. Note that this could be trigged by the failover partner connection string attribute, and that the database may no longer exist or may be offline, single user, etc. | |
| 56 |
Error: 18456, Severity: 14, State: 56. Login failed for user ‘<x>’. Reason: Failed attempted retry of a process token validation. |
| State 56 is not very common – again, like states 11 & 12, this could have to do with UAC, or that the domain controller could not be reached. Try changing the service account for SQL Server to a known domain or local account, rather than the built-in local service accounts. | |
| 58 |
Error: 18456, Severity: 14, State: 58. Login failed for user ‘<x>’. Reason: An attempt to login using SQL authentication failed. Server is configured for Windows authentication only. |
| State 58 occurs when SQL Server is set to use Windows Authentication only, and a client attempts to log in using SQL Authentication. It can also occur when SIDs do not match (in which case the error text might be slightly different). | |
| 62 |
Error: 18456, Severity: 14, State: 62. Login failed for user ‘<x>’. |
| State 62 occurs when a Windows Authentication account tries to access a contained database, and the contained database exists, but the SIDs do not match. | |
| 65 |
Error: 18456, Severity: 14, State: 65. Login failed for user ‘<x>’. Reason: Password did not match that for the user provided. [Database: ‘<x>’] |
| Contained user exists, the database is correct, but the password is invalid. This can also happen if you use a SQL login to connect to a contained database that has a contained user with the same name but a different password (one of several reasons this is not recommended). | |
| 102 103 … 110 111 |
Error: 18456, Severity: 14, State: 102. Error: 18456, Severity: 14, State: 103. Error: 18456, Severity: 14, State: 104. Error: 18456, Severity: 14, State: 105. Error: 18456, Severity: 14, State: 106. Error: 18456, Severity: 14, State: 107. Error: 18456, Severity: 14, State: 108. Error: 18456, Severity: 14, State: 109. Error: 18456, Severity: 14, State: 110. Error: 18456, Severity: 14, State: 111. |
| Documented by Microsoft as Azure Active Directory login failures. | |
| 122 123 124 |
Error: 18456, Severity: 14, State: 122. Error: 18456, Severity: 14, State: 123. Error: 18456, Severity: 14, State: 124. |
| According to Microsoft, these indicate a blank or missing username and/or password. | |
| 126 | Error: 18456, Severity: 14, State: 126. |
| The docs say «Database requested by user does not exist.» But it’s not clear why you would get 126 instead of, say, 38 or 40. | |
| 132 133 |
Error: 18456, Severity: 14, State: 132. Error: 18456, Severity: 14, State: 133. |
| Documented by paschott and by Microsoft as Azure Active Directory login failures. | |
| 146 147 148 149 |
Error: 18456, Severity: 14, State: 146. Login failed for user ‘<Windows auth login>’. Reason: Token-based server access validation failed with an infrastructure error. Login lacks Connect SQL permission. Error: 18456, Severity: 14, State: 147. Error: 18456, Severity: 14, State: 148. Error: 18456, Severity: 14, State: 149. |
| These states replace states 11 and 12 above, but only in SQL Server 2016 or better. The goal was to make the actual underlying issue easier for the sysadmin to diagnose between SQL auth and Windows auth logins, and between connect and endpoint permissions (all without giving any further info to the user trying to log in). For more details, see the latter part of this post. |
I am sure I missed some, but I hope that is a helpful summary of most of the 18456 errors you are likely to come across. Please let me know if you spot any inaccuracies or if you know of any states (or reasons) that I missed.
If you are using contained databases, there will be a little extra complication in solving login failures, especially if you try to create contained users with the same name as server-level logins. This is a ball of wax you just probably don’t want to get into…
Thanks to Jonathan Kehayias (blog | twitter), Bob Ward (CSS blog | twitter), and Rick Byham for input and sanity checking.