Upgrade to iOS8.04 no playable tracks on device - iphone5s

I play music via the Deezer app in my car through an ipod dock.

Since upgrading to 8.04, my car says there are no playable tracks on the device.

I know there are sync'd albums and playlists, as well as downloaded Deezer music - and it all worked perfectly the previous day, until i upgraded to 8.04

This is the only change i have made so assume it has to be that.

My other ipod plays fine through the dock, but that is an older device (ipod classic).

Any advice?

Tried searching for nothing specific coming up for 8.04.