Troubleshooting:
Music is not playing from all Sonos speakers – Desktop
Solution: Group all Rooms in Sonos app
1. Install Sonos app for your computer.
2. Open Sonos app on your playback device. Go to Rooms > Group.
3. A pop-up will open. Check all Rooms > Done.
4. Open Atmosphere. Go to Settings (⚙) > Select Output Device > Connect with your Sonos group.