Hello Kalamanchum,
We see you're having issues playing audio from your car's stereo, and we'd like to help.
Are you using CarPlay? If so, try out the steps from here: If you need help with CarPlay
If you're not using CarPlay, are you able to stream the music via Bluetooth to your car's stereo, if that's a supported option?
You can also try using a different Lightning cable, as well.
Lastly, be sure to also check that the audio output is being routed to the car. After selecting a song to play, tap on the AirPlay icon at the bottom, and see if that lists your car's stereo or not.
Cheers.