The customer mentioned that all of the sudden they are seeing authentication prompts in the GSS web console and the regular console.
They get this message:
User - MyUsername is not explicitly added or part of any group configured in Security settings of GSS.
This is happening for all users who login to the GSS Server.
The customer found that someone had deleted the security group that was originally assigned access to this users under Tools>Security.
GSS 3.3 RUx
Try to login to the regular GSS Console with the ghost server account that you used to setup originally and add a new group that contains all the users (under Tools>Security>Manage User Groups) that needs access to your GSS Console.