SQL Server error 18456 cannot connect – SQL Server 2017 LOGIN FAILED ERROR 18456
Normally error code comes up with a description that gives us a hint about what has gone wrong. But in this case of SQL Server error 18456 on screen, no cause of login failure is displayed. This is an intended development of the application in order to have protection against unauthorized users hacking the server on basis of guess information. However, the administrator can check out the event log in order to get details about occurrence of SQL Server error 18456.
Cause of this error of Microsoft SQL Server login failed error 18456:
1: At the time of Server login, if either of username or password is incorrect, the error will be generated.
2: When an SQL Server instance is logged in for the very first time, possibility is that the users encounter SQL Server error 18456. This happens normally when the “Windows Authentication” is enabled on SQL Server under the security section and SQL Server is unable to recognize the windows user trying to login.
3: For SQL Login the next possibility is that the password for login is expired. This will also can also error same while disabling the username on server.
Steps to Fix the Microsoft SQL Server login failed error 18456:
- Before any troubleshooting steps, make sure that the login credentials that is username and password entered is correct for SQL Server login.
2. If Windows Vista or Windows 7 is used, then run SQL Server through Run as Admin option. This might give a solution.
3. If Windows authentication is enabled and the error is received, then use the SQL SA credentials.
4.System Admin SA Username and Password is important, so keep it safe. If SQL Server authentication mode is used to login to Server, then SQL System Admin credentials would be required. Before login check out that the password is not expired. For that, open SSMS, right click on server name and choose “Properties”.
5. To check password expiration is enabled. For that go to SQL SSMS and go to properties on login and in “General” tab and see if “Enforce Password Expiration” is enabled or disabled.
6. If AD Account then in ADUC check on the account used to see in properties that in “Status” tab and find out if the account is locked. If the account is not locked, the “Login is locked out” will be disabled.
If locked then unlock the account
7. If the authentication mode is changed, then do not forget to restart SQL Server to allow changes to take place.
Please follow the above mentioned fixes which can help to fix Microsoft SQL Server login failed error 18456. However, if the above procedures failed to fix SQL Server error 18456 then one can also go through SQL password recovery tool to reset lost SA password of SQL Server.
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