Song will download onto iPhone but it cannot be played?

[Unholy_Vibes95]

I have been having so much trouble on this. I have been trying to add a song I bought off of iTunes onto my Spotify mobile app. I have tried downloading it while it is playing on my computer through my phone (it usually works); however, i switch to listen to it on my phone, it automatically stops playing. The song is Anywhere But Here by Five Finger Death Punch and Maria Brink if that helps.