This forum is intended for all discussion regarding GATC (Global Air Traffic Control), the most versatile ATC simulation to date covering close to 14000 airports!
The problem is for sure a local problem on your system. Make sure that your system meets the system requirements on the product page and read the manuals how to operate this aircraft.
Thought I would try Olaf's settings. Both Captains and FO's radio's COM-1 and COM-2 seem to function properly. Just firing it up but will give it a short flight.
The same problem here - only ATC answers can be heard. Also no text for outgoing calls. ATIS also in a loop with the first words of the info. In default A320 no problems.