You should be able to access the Air Traffic Controll functions in a stock X-plane 11 installation by pressing ENTER. Xplane hey calls it RETURN, same thing.
I you cannot access the ATC functions in your Xplane 11, try this:
- Open SETTINGS (mouse up top-right to icon LEFT Help)
- Click Network, it’s in the top menu, 4th on the right.
- Click Reset Network Configuration, bottom-left of this menu.
- Click DONE .
You should should now be able to Press ENTER and get ATC again!
Here is a picture that should help you find it: