Found the solution.
I installed VLC.
It said my file was “wrapped with mp3wrap.”
I had merged two mp3s using mp3wrap.
So I opened it up with VLC and converted it to a “normal” mp3. 
Now it plays on my phone.
Found the solution.
I installed VLC.
It said my file was “wrapped with mp3wrap.”
I had merged two mp3s using mp3wrap.
So I opened it up with VLC and converted it to a “normal” mp3.
Now it plays on my phone.