My comms grey out and i can't communicate with atc

[Ethan Lacey 0]

I keep getting this issue in the PMDG 747 and QW787, it started last year, since then I got a new PC and it continued to happen. I have also searched everywhere to see if anyone else has had this problem, and haven't found anything like it. It happens at completely random times, usually after push, but sometimes before and once it happened mid flight. any help would be appreciated.