cant use other apps while listening to deezer

I've had deezer for over 10 years and absolutely love it but for the last few months I've been having a problem and it's really putting me off. 

I've always been able to put deezer on in the background and go about my business on my phone- including playing games- without any problems.  Obviously there was the odd time when an Advert came on and would play over deezer but that was easily sorted and not too much of a bother as I could pop i to my notifications banner and press play and go on as before.

Now it doesn't matter what app or game I try to use while listening to Deezer- the minute I start to open up the app or game my deezer will stop playing and will be removed from my notifications bar! 

This is driving me insane!!

I've tried changing app settings, clearing cache and data, turning off battery optimisation and no change.

Please help