I recently got a new iPhone 5S as opposed to my current 4S. I haven't started using it as my phone because I got it so that I may travel with it, but I've synced it and put all of my apps and data from my 4S onto it.
When I put an mp3 files into my music folder, it automatically syncs with spotify on both my computer and 4S. When I connect my 4S to my computer and turn on WiFi, these local files start downloading onto my 4S, and I am able to play them easily both offline and online after they have downloaded.
However, even though my 5S indicates that these local files have downloaded (with the green download icon in spotify), when I play them, there is no sound. I can play non-local downloaded music just fine, but only the local files have no sound.
If any additional information would be useful, please tell me and I'll see what I can do. I browsed the internet for a solution to this, and I can't seem to find it, so help would be extremely appreciated.