Problems with sound via cable when BT is activated

[M.Hulot]

I was using Neutron for two years on my Blackberry Classic (OS 10) without any problems. Now I use it on my Blackberry Priv (Android) and have problems with transferring sound over Bluetooth or jack cable to my car.
If Bluetooth is activated on the Priv (not only on the Neutron MP), there is no sound via cable, unless I disconnect and connect it several times. But I don't know, why these attempts are neccessary.
If Bluetooth is not activated on the Priv, there is sound via cable - but this means that I can't answer calls with my car's BT equipment.
Transferring sound via BT to the car radio works, but has several interruptions all the time. So this is no alternative.

Does anybody know what to do?