If you created the database login before the server login, you can't just create the server login. You need to delete the user created in the database, then create the user in the server.

>I think you are maybe on to something. I created this database on my SQL Server and then attached it to the customer SQL Server. What I don't understand is I never created a user in my SQL Server. Do I am trying to figure out what you mean by "delete first the login at the database". How do I find out if this login exist? Thank you.