You cannot access the GFI MailEssentials Configuration UI while trying different user and password combinations. The login page displays the error 'Username, password or domain is incorrect!':
You need to provide the credentials of the user that was used to install the application.
Usually, this is the
<domain>\Administrator user account but this may be different depending on your environment.
If you no longer remember the password for this account, you can reset it from your Active Directory.
While resetting this password will not affect GFI MailEsentials in any way, other aspects of your environment may be affected, so exercise care while performing this.