You connection should be a System DNS on your FileMaker Server computer where you also save the Username and Password inside the DNS. With this you get a possibility to use that data source tables inside your own database and this is called ESS.
You can read more about ESS here
I have of course set all this up already. The server connects through a system DSN and all works perfectly on the PC clients.
It does not work when we connect with FM Go however.
What kind of action is failing when you try to use your ESS tables? Scripts/Layouts?