The archive server that hosts the vault archive manages user authentication. You can use Validate Logins option to validate the user account.
If the correct credentials for an active vault user account are not found on the archive server, the user account is listed in the Administration tool with a red plus symbol. Such users may not be able to log in to the vault until the issue is resolved.
To validate user accounts:
Right-click .
If you validate windows users from a large domain, Validate Logins may take a long time to complete.