[Microsoft SQL docs]: 'Login failed for user' (Error 18456) means the username or password is wrong, or the login is disabled: ask the service administrator for valid credentials. To check a disabled login, run SELECT name, is_disabled FROM sys.sql_logins in master; enable it with ALTER LOGIN [name] ENABLE. If the login does not exist, create it with CREATE LOGIN in master, then create the user in the target database and grant permissions. Save the tracing ID from the error message for support.

Context: 18456 is never a network error. Check the login itself.