Spotify background playback problem on iOS
Sometimes, Spotify stops being able to play music on iOS when it’s sent to the background. Whenever this happens, you may have to free up memory by removing some background apps.
For me, this seems to occur when there are many active programs in the background. Although apps shouldn’t consume memory when they’re suspended, they seem to at least take up some small amount, because shutting them down always fixes the problem.
Whenever Spotify stops being able to play music in the background, just open the app switcher and remove some background apps. This will make Spofity work again, although a restart may be needed.