Spotify users on Android who rely on Offline Mode are wearing thin on a chicken & egg problem. Details here: https://tinyurl.com/yascap77. This video is my attempt to make someone at Spotify understand the issue enough to care to fix it. I am a developer, and if I saw this video about my product, I'd take enough pride in my craft and have enough care for my users to fix this.
The gist of the problem is you put the app in Offline Mode. You are happy. You open Spotify one day and BOOM...you are not logged in. HOWEVER, you can't login because you are in Offline Mode. You have to login to access settings to turn off Offline Mode. Only solution is to uninstall and re-install....and then re-download all your music you want to use offline.