I’m referring to this screen:
When I click the Intercom or Group button, I’m sent to a different tab and I can’t seem to get back to the screen shown above.
The back button isn’t responsive, and closing out and going back in to the Communication window doesn’t work (it stays on either the Intercom or Group tab).
I’m not sure whether this is a bug or not.
Moved to User Support Hub
bind it in the communication under ATC communication
Isn`t it this one here: ^ on the keyboard by default? Thats what I do…
This might have been indicative of a bug – the COM1 tab wasn’t showing up.
I restarted the game and now it’s appearing, and I can access the ATC conversation through that.
Yes, I believe so.. see COM1, COM2, COM3 tabs disappeared from ATC window - #8 by Anonyrootmous and maybe ATC Panel doesn't show comm options - #74 by Cliffyboy1962 and upvote. This is so annoying 
EDIT: Maybe a fluke but this now seems resolved for me after I removed mobiflight-event-module from my community folder. It was used by Auto-FPS and I also removed Auto-FPS. Fingers crossed, hope that helps others.
