I have been having problems with this since the 2.1 update. I originally had issues when 2.0 was released but set up my phone as new when I got a 6s and had no problems since then. Then recently I started having problems again. The delete all music trick worked but the apps stopped working once I reloaded the music again after a seemly random amount of time (a couple of hours to a couple of days).
My theory is it is related to apple music offline downloads. I deleted all my music recently and it is all working again then reloaded my music to my phone but haven't downloaded any of my apple music stuff for offline listening and haven't had a problem yet, although it has only been 24 hrs. Am in contact with apple about this and expecting a call from an engineer soon so will update. Could it be a particular song or two messing things up?
My theory is it is related to apple music offline downloads. I deleted all my music recently and it is all working again then reloaded my music to my phone but haven't downloaded any of my apple music stuff for offline listening and haven't had a problem yet, although it has only been 24 hrs. Am in contact with apple about this and expecting a call from an engineer soon so will update. Could it be a particular song or two messing things up?