All of a sudden yesterday I started to see the above message when playing any song in Apple Music and when accessing Settings I had the ‘Join Apple Music’ option available. I tapped it and the above message just came back.
A reboot did not help and so I contacted Apple Support via chat (phone calls not available after 5:45pm).
After a long discussion in which I got the impression that the agent was talking to multiple people because of how long it took him to respond (think he was based in India?) he advised me to sign out of iCloud and then back in again.
This is a pain to do, but I did so and it made no difference apart from taking hours to retrieve my photos and notes etc again. He then advised to reboot again and I of course lost the chat.
I opened the case again and ended up chatting to someone else in India who advised me to reset all settings. I didn’t want to do that and asked if it would definitely resolve all of the problems. He said it might and that he ‘had a list’ of options to go through. I ended the chat.
The plan was to call Apple today, but a solution was on reddit as it happens. Sign out of iTunes and App Store in Settings and try to start a free trial of Apple Music using my normal iCloud ID. It worked instantly and all is fine now, no thanks to the hour spent chatting with Apple reps who seemed to be randomly trying things that were much more intrusive than needed.