Iphone Stopped Playing

I've had my 2013 Prius since 2015. I used a USB cable to connect my Iphone to the car., and play the music on my iphone on my car. This has worked fine since 2015.

A few days ago I found the car recognized the iphone, but can't 'load' the music.

What I see is it will automatically start playing a songfor about 30 seconds, then stop. If I go to select another song, the screen says 'loading' and never plays. I let it try 'loading' for 20 minutes once, it never loads or plays any music.

The phone itself plays music fine. It plays through headphones just fine. I bought a new USB cable, and that made no difference.

I'm stumped - the car recognizes the phone. It just can't play music for a few seconds.

Anyone have any ideas?