AirPlay connection problems

[Asu]

I was playing from the Music app from my computer running 13.1, using AirPlay, to one of my AppleTVs, lets call it AppleTV1. I have also streamed music to another Apple TV (let's call it AppleTV2) from the same computer, same Music app. Last night I turned on an institutional VPN (Cisco Anyconnect) and the stream to AppleTV1 was disconnected. Later I closed Cisco, but then I became unable to stream to AppleTV1 , but remain able to stream to AppleTV2. AppleTV1 remained selectable (both in Music and the Sound menubar dropdown), it turned on (and it turned on the connected TV, an LG) when selected, but no sound was played and after a short while the checkmark in the Music app turned into a minus sign.

I deactivated the Cisco filters and restarted the computer. Now, when I try to stream to the AppleTV1, I am greeted with "Sign in to Apple Music to play songs on your Apple TV." Which I didn't have to do before. I sign in but nothing happens, I get the same sign-in request over and over again.

Meanwhile, I can stream to the AppleTV1 from a YouTube video in Safari on the computer.

My iPhone does not see AppleTV1 at all in the AirPlay list, interestingly it sees the LG TV that is connected to AppleTV1, which is not seen from the computer on the Airplay list.

I hope I managed to make it marginally understandable. My initial guess is that I need to delete some corrupted preferences. Any help would be most welcome.

Thanks.

 

[Asu]

Well, computers are interesting creatures. You eff around long enough, things begin to get shaken back to normal.

I tried to log in to Apple Music from a google link instead of from the Music app, which caused the open Music app to crash. That caused things to go back to the way they were right after closing Cisco - i.e. I was again not asked to log in to Apple Music. Then I did a few other random things, many of which caused subtle changes towards a more normal operation, eventually almost everything worked on AppleTV1, even the name of the song showed up and stayed on the screen - except there was no sound. For no other reason than to do something random again, I added a password to the AirPlay settings on AppleTV1. I tried to connect, got the pw window, typed in the sucker and - tada! the music sounded up!

I know what I did but I have no idea why I did them, other than knowing that this random tinkering approach worked with problems (like e.g. printer settings) in the past. My guess is that eventually settings get overwritten by the many various triggered processes and if I'm lucky enough, things go back to normal.

Thanks for listening!