Loss of sound and audio won’t switch on

[minshy]

Hi,
I have a 2018 transit custom with a sync 3 head unit.
I was listening to music through Apple CarPlay and the sound disappeared.
What I now have is the head unit switches on, the home page I it says audio off, when I press either the touch screen it tries to switch on but nothing happens, it’s the same with the on/off button. I try and press the audio symbol which would change the unit to radio and this also does not work.
What I can get my head round is the rest of the buttons I press work, I can switch to the phone, settings and connect CarPlay and this shows everything it shows the music playing but no sound.
I have checked both audio fuses which appear to be OK.
Can anyone give me any pointers on where to go from here

[minshy]

I forgot to add i have tried the soft and master resets and this did not alter anything.
I have changed the battery as this needed changing more or less at the same time