vPilot TX/RX grey when connected

I was holding short a runway and I just randomly unable to hear the ATC as well as ATC unable to hear me. I have experienced this twice. I was using the Fly By Wire A32NX while both incident happened. The only reason I might suspect is that I pressed the T.O config before taxing, however I can listen to ATC and ATC can read me while I was taxing. This is extremely furstrating for me. If there is a way to solve this problem, please notify me. Thanks!

Usually that means that you are not getting power to the radios. You should check that the next time this happens.

I have got my engines running, what else can I check to power up the radio again?

I don’t fly that aircraft, so am not sure. Perhaps someone else in the community might be able to chime in.