I tried everything else suggested here, but nothing helped. Then the following worked for me: go to the "widget panel" by swiping right on the home screen. Scroll down to the very bottom and click the "Edit" button. If the "Music" widget is on, turn it off, and if it's off, turn it on and then off again. Then click "Done," and then restart phone. If that doesn't work, try restarting the phone twice: once after turning the "Music" widget on, then again after turning the "Music" widget off. Try various combinations of this until it works— it did the trick on 2 different phones of mine. I think it's definitely a "widget" issue!