Usually this is the user that you logged in with when you installed SQL Server or the user that is the default administrator on the computer. You need to figure out what user does have rights to SQL server. In the below screen shot, I am logging into Microsoft SQL Server Management Studio with a user that does not have administrative permissions to connect to the server. Stick around after you fix this problem to learn how you can avoid many potential problems in the near future by learning a few fundamentals about dealing with SQL Server and inevitable SQL server issues.

The generic message 'Login Failed for User (Microsoft SQL Server, Error: 18456)' means you entered invalid credentials when logging into SQL Server. In this post, I will teach you how to determine what user has administrative rights on the server as well as walk you Step-By-Step how to configure SQL Server to allow other users to login as Administrators to SQL Server.