Wrong certifications: This is presumably the most widely recognized explanation behind error 18456 but then, we like to zero in on the moment subtleties. Check if your qualifications are correct. In the event that you are signing in unexpectedly, ensure you got the correct qualifications from the manager.
UserID handicapped: If the UserID hasn’t been conceded admittance to the SQL Server then this error will be tossed. Once more, on the off chance that you are attempting to login unexpectedly, we would prescribe reaching the overseer to ensure that your UserID has been allowed admittance. mistens.com
Various conditions of the error: As we referenced there are various conditions of the error and once you comprehend what the various states mean, it is simpler to determine the issue:
On the off chance that the error state is 2 or 5, at that point that implies the UserID is invalid and you have to watch that.
Error State 6 methods the client is attempting to utilize a Windows Login name for SQL confirmation which the worker can’t comprehend.
An error condition of 7 implies that either the login has been crippled or there is a secret key befuddle
Error state 8 methods there is a secret key bungle