a lot of head units wont play certain types; usually flac for instance, but i dare say some might struggle with mp3 unless its done right way…or perhaps it cant see past track one. maybe try just using music on phone and see if that works. it would cut down the possible reasons
Current Car: Hyundai Kona Premium EV...2 way 40kg hoist
Last Car: Toyota C-HR Excel Hybrid...4 way 80kg hoist