Tester Agents not connecting

 

My Tester Agents dont want connect to the cloud. All agents are still disconnected. In my Profile i can not see any agents. Account is entered ans "Selling throu Community" Checkbox is enabled. My Client is behind a NAT device. Is there something else to configure? I tried do reconfigure the scheduler so all ON as well as all OFF. Both Settings dont changed the behavior.

I found an forum entry from 2013 which says, Tester Agents are not supported on virtual machines? Is that still correct? Could that be the reason of my issue?