The field maintenance screen sits behind a authentication screen that, unlike the Redbox Desktop, verifies credentials with redbox servers (which are no longer online). To get around this, @viper33802/@loki patched the DLL that has todo with the authentication. The steps are as follows:
Using the previously mentioned instructions to access the Field Management login page , type in any value for the username and password and click login
SUCCESS! You should now be logged into the Field Maintenance Menu