My car no longer recognizes media on my iPhone 7
I figured out how to fix it:

(You Must Have Apple Music with one song at least). 


Power cycle your phone by powering off and powering on.
Open Apple Music and play any downloaded song.
Connect USB/lightning cable while the music still playing on the phone.


Now you can see the song name on the screen and controllable by steering wheel, and you can use any app that plays music it will be compatible.