Fix orphaned SQL Server users

--lists the orphaned users:
EXEC sp_change_users_login 'Report'

--If you already have a login id and password for this user, fix it by doing:
EXEC sp_change_users_login 'Auto_Fix', 'user'

--If you want to create a new login id and password for this user, fix it by doing:
EXEC sp_change_users_login 'Auto_Fix', 'user', 'login', 'password'

An invalid parameter or option was specified for procedure ‘sys.sp_change_users_login’.
pas NULL as 'login' parameter