Spotify related issues

If you are transmitting through "Spotify Connect" you can on some devices only adjust volume when the app is open. This means you can't adjust volume on the volume buttons on the side of the phone when the app is minimized.

- Only the transmitting device can adjust the volume. Spotify recently released a group feature allowing other devices to adjust the volume if they join the music session on the device. You can also try Google Cast instead, here everyone on the same network, can change song and volume.

- Your phone has lost the connection or the connection session has timed out to lower battery usage. Just start a new track, and it should wake up again

Check network settings, and if the setup in Google Home app is completed.
If the issue persist restart your phone.

Check if the service is unavailable https://downdetector.dk/problem-fejl/spotify/

This should have been fixed by Spotify at start 2021. The issues was that the service started playing out of thin air, with songs no one has asked for.