Remove db_denydatawriter, db_denydatareader role from admin user
If you need to reset your permissions for the master user to the defaults (dbo access in each database), you can reset the master user password from the AWS console and Apply Immediately to have changes take effect.

Here are the steps to do this:


Go to the AWS Console
Instance Actions -> Modify
Under Settings type in a new password for the master password.
Select Apply Immediately