Sonos not responing to any controller (iOS or Windows)

As if this new Sonos iOS app wasn’t bad enough, we have now lost control of our Sonos system it seems.

First, I could not stop music from playing on any iPhone in the house. The play/pause icon would toggle on screen, but the music just carried on. The only way I could stop it was to use the Windows controller, where play/pause would also not work, but deleting the music from the queue worked.

But now I can’t get anything to play. The selected song is moved to the queue and the icons suggest it is playing, but it is not.

So the whole system is now non-functional. Any suggestions welcome...