I re-authorised Amazon Music. (BTW, I used to get and Amazon Prime stream: I assume this has now been replaced with Amazon Music. I am an Amazon Prime member.)
There is an earlier thread for this error from 22nd Sept but it was apparently resolved.
Amazon Prime is playing file through my Amazon Echo.
Any suggestions would be welcome.
Best answer by Max P
Like many of you are already aware. Amazon Music on Sonos is restored and working.
It's possible you may still experience some album art not displaying in all controllers. We're looking into this as we speak.