Sgt. Ear Ache
100+ Head-Fier
I had this exact same problem, butit was doing it constantly. I read it might have something to do with reaching the limit of 8 offline devices registered on one account. I never had 8 offline devices, but logged into my account to check, and it had my Samsung tablet registered, about 5 times for some reason, meaning I had hit the limit.
I cleared all these registered devices, and when I booted the M6 back up, it seemed to have fixed the issue. However, I tested the M6 offline with Spotify, and it worked, but when I next booted it up, it had logged me out. It wouldn't let me log back in, saying I was offline. I couldn't go online without logging in.
This was a free trial of Spotify, and I cancelled it, and went back to Tidal.
I'm a Spotify subscriber but I'll check the offline devices suggestion...could be the problem.