My 20 Audi S5 MMI and my Apple iPhone OS 15 have always been Bluetooth compatible. Until today. To troubleshoot, I’ve deleted my phone from MMI and deleted MMI and repaired with my phone. The two connect but there is no audio. On the car screen is the message source not supported. On my phone I see the audio and MMI source are connected. They worked perfectly this morning. This afternoon not. Any ideas? I am not using USB cable - strictly Bluetooth. Thanks for your help!