Call failed using iPhone on macOS

Hi. I have a problem maintaining a connection during a conversation using facetime on macOS. When I receive a call from an iPhone, after a few / several seconds I receive a message: Call Failed on macOS. The conversation is still ongoing, the computer is still indicated as the audio source, but the caller cannot hear me. That's why I need to quickly change the source on the iPhone back to speakerphone or microphone.

Is there any option to find out the reason for this behavior? I tested on...

Call failed using iPhone on macOS