Hello David Estes,
Welcome to Apple Support Communities!
We want to help get AirPlay working normally on your Mac so the music doesn't stop.
Use these steps first for an AirPlay related issue:
"After each step, see if you still need help.
- Make sure that your AirPlay-compatible devices are turned on and near each other.
- Check that the devices are updated to the latest software and are on the same Wi-Fi network.
- Restart the devices that you want to use with AirPlay or screen mirroring.
If you're prompted to enter a password, you might have restrictions turned on, or you might need to adjust your AirPlay password settings.
Still need help?
If you have another issue using AirPlay, learn what to do.
If your music unexpectedly stops
If your music stops playing unexpectedly, use your device or Siri to start playing music again. In some situations, the Home app might be using your HomePod,* Apple TV, or AirPlay-compatible speaker as the main audio source for streaming music (even if your HomePod* or Apple TV isn’t currently playing music). Using Siri on that device or performing another task might cause playback to stop everywhere. You can also use an iOS device or computer with iTunes as an audio source to manually stream music instead."
This Apple Support page has the full details: If screen mirroring or streaming isn't working on your AirPlay-compatible device - Apple Support
We hope these steps can help isolate and resolve the issue so you can enjoy your music without disruption
Cheers!