I noticed that your RAAT zone does not show a volume value but your AIR zone does. Can you play to your Expert Pro via AIR?
I’m asking this because I had a somewhat similar issue that I posted here:
Devialet AIR worked fine, but RAAT did not. RAAT remained as a selectable zone but no volume value. My post describes what happened. I did try rebooting everything router included to no avail. Strangely enough, swapping my ethernet cable seems to have resolved it. You might want to check your RAAT zone Device Setup -> Volume Limits to see what the values are.
You indicate you’re streaming via wifi so it’s unlikely the same issue. Still, very strange.