It is clear from searching Airplay on this support page and Google that something has happened to multiple users to stop Airplay from working seamlessly with Sonos products. I play music to my Sonos Era 100s and 300 once or twice per month via airplay but tonight it is not working. I tried resetting all devices per other posts and factory resetting etc…. Best case scenario it will play a song for like three 3 minutes and then drop and not play further until I reset everything again. This used to be seamless. I dont have further time to troubleshoot this but somebody either at Apple or Sonos has dropped the ball here. If its Sonos please fix asap. If I cant get this stuff to work next time I need to play music I am just going to ditch all my Sonos products and switch to Bose which is shame because I thought the Sonos sounded better than Bose. But Sonos is useless if the Airplay wont work.
Reddit has some threads on this too - here is one