Downgraded from Tidal HiFi and now no sound

Hi folks - I downgraded my Tidal subscription from HiFi to Premium as I wasn't using it enough to justify the extra. Since then, I get no sound from Tidal through either my Touch or Radio, connected to a LMS server on a Pi. The file appears to play but no sound emerges - I can see that the format is still FLAC, which I guess may be the source of the problem. Whichever option I choose in 'streaming quality' makes no difference.

I've tried adding and removing the Tidal account in mysqueezebox, same for the Tidal app itself, still no joy. Any ideas grateful received!