Balena Sound Rpi4b Release 3.10 OS 6.3.18 No audio 3.5mm jack

Balena Sound brand new Rpi4b Release 3.10 on OS 6.3.18 installed using DEPLOY button and NO modifications from the defaults.

I have just bought a new RPi4b specifically for Balena Sound. I have used the DEPLOY button and chosen the RPi4b option. I am using wired ethernet. Spotify finds and ‘plays’ but no sound is output from the 3.5mm jack. Spotify was started via network (app on phone). Also no sound output if I connect from phone via Bluetooth.

I also tried via the RPi HDMI port with an HDMI audio splitter - but that did not work either.

I have looked at other posts but they are from 1 or 2 years ago so I would rather have help with it while it is still in the ‘default’ state

Spotify does work with my VolumeIO setup.

Is anyone able to offer any help before I change anything as the ‘default’ deployment to a standard RPi would seem to ‘work out of the box’
Thanks