If you are restoring an MS SQL database, it is possible that some database users will be orphaned. In order to provide the ability to access and use the database for these users, you need to repair them.
To check if a database has orphaned users and to repair them:
Go to Websites & Domains > Databases > database name.
If you see a warning saying that there are several orphaned users that should be repaired in order to function properly, you have orphaned users who need to be repaired.
To repair orphaned users, click the Repair now button corresponding to the users you want to repair.
Provide password for the users and click Repair.
If a user is supposed to be a system user without a password, leave the password field empty and click Repair.