ipod shuffle (2nd generation) and big sur

When I upgraded to Big Sur my little shuffle that I use at the gym refused to play my tracks. I get only the message: Please use iTunes to sync this ipod.

My Finder and Music/Books recognise the shuffle and indeed and indeed tells me the tracks are still there. I have tried syncing in all the usually ways - they seem to work - and manually managed a retransfer of the track. It is definitely there on the ipod.

I can play the track from the shuffle when it is physically connected to iTunes but not when it is disconnected.

I have erased the ipod, reinstalled factory settings and retransferred the track again.

All seems fine except nothing plays on the shuffle except that extremely irritating message.

It worked fine under Catalina.

Anybody know what's going on?