EDIT:
So guys i got it working by adding a variable : SOUND_MODE and set its value to STANDALONE,
as i am not interested in MultiRoom 
Thanks for the detailed explanations on your website and again i really appreciate all your work
Hello guys,
just installed everything according to the getting started guide on balena sound.
configured my dac and it plays audio through my dac.
But i wanted to use it in a room where i dont have access to the internet as a bluetooth audio receiver. The problem is if i disconnect it from the internet it stops playing music (bluetooth connection is still there). if i connect it again it works fine.
I didnt really configure anything with the CLI deploy and just let the settings default.
If i quit the multiroom server it also stops working ? Im not using multiroom just bluetooth.
multiroom-server Starting multi-room server…
multiroom-server 2021-08-27 13-18-22.577 [Error] (Avahi) Failed to create client: Daemon not running
multiroom-client 2021-08-27 13-18-23.542 [Error] (Controller) Failed to send hello request, error: Operation timed out
multiroom-client 2021-08-27 13-18-23.542 [Error] (Controller) Time sync request failed: Operation timed out
multiroom-client metadata:{“STREAM”:“balenaSound”}
All services are running by default.
Im playing music from my smartphone via spotify per bluetooth to the raspberry pi (balena os8776).
multiroom-client metadata:{“STREAM”:“balenaSound”}
multiroom-server 2021-08-27 13-08-37.420 [Error] (StreamSessionTCP) Error reading message header of length 0: End of file
multiroom-server 2021-08-27 13-08-37.421 [Error] (StreamSession) StreamSession write error (msg length: 2519): Broken pipe
multiroom-server 2021-08-27 13-08-37.421 [Error] (StreamSessionTCP) Error in socket shutdown: Socket not connected
Raspberry Pi 4
[balenaOS 2.80.5+rev1]
12.8.7
HifiBerry DAC2 HD
I gave support access to my device.
btw i really appreciate all of your work here. on other services youd have to pay just to use bluetooth audio.