Media Centre problems

So, Audi A6 50. Beast of a car. But... I have digital cockpit and up to a few days ago my iPhone was playing back in the car my iTunes library via Bluetooth. Absolutely no problems at all. For a few days now nothing. It sees the tracks and the artist but not the albums. And selecting a track , it doesn't load. This happens on every artist, every track. The volume control is greyed out. Tried a reboot on the iPhone (7 plus) and still nothing.
It sees my phone for phone numbers and works fine with that. It 'sees' my phone when I start the car. Their is no sim card, no cubic connect enabled but that was always the case.

Anyone any ideas ? I wonder if some form of MMI re-boot would work but I don't know how to do it.

Grateful for anyone's help.

DaveW said:

You can try a reboot of the MMI by switching it on, then once loaded up, press and hold the volume button for about 20 seconds.
Has your phone had a software update? Things like this only usually stop working if something has changed.
Good luck,
Dave

Click to expand...

MMI reset but did not solve problem

This problem appears solved. I upgraded my iPhone software to iOS 13.5 and it works. I'm wondering whether the fault was when the battery was low in my iPhone ?....so Bluetooth was compromised.