Topic Status: Some information in this topic is preview and subject to change in future releases. Preview information describes new features or changes to existing features in Microsoft SQL Server 2016 Community Technology Preview 2 (CTP2).
The user attempted to login with credentials that cannot be validated. Possible causes are:
The login may be a SQL Server login but the server only accepts Windows Authentication.
You are trying to connect using SQL Server Authentication but the login used does not exist on SQL Server.
The login may use Windows Authentication but the login is an unrecognized Windows principal. An unrecognized Windows principal means that the login cannot be verified by Windows. This could be because the Windows login is from an untrusted domain.
Similar problems can cause the less-specific error 18456.
If you are trying to connect using SQL Server Authentication, verify that SQL Server is configured in Mixed Authentication Mode.
If you are trying to connect using SQL Server Authentication, verify that the SQL Server login exists.
If you are trying to connect using Windows Authentication, verify that you are properly logged into the correct domain.