Support output to AirPlay devices

Hi,

I'm currently on macOS Catalina, and I've installed this software from the release panel and not from homebrew.

Yesterday I've tried it using headphones, and it worked like a charm, then I've decided to use my AirPlay server so I can listen to music using external speakers, and suddenly it stop working.

I've chosen then, from System Preferences, to chose background audio as a default output device, but it doesn't work, I can't change the volume of Safari (yesterday I could), and from the menu, my AirPlay server is not listed.

Here it doesn't work (as I think it should)

Here it should work

But it doesn't and also the AirPlay server is not listed.

At least, choosing the AirPlay server as a default output audio device it doesn't work

But now the AirPlay server is shown, but if I choose Internal Speaker or Raspberrypi nothing changes (the audio still comes out from the raspberry)

So i was wondering, how? how can I make it work? am I doing something wrong?