While driving a car, using whatsapp

I can’t listen voice messagge from whatsapp when my iphone7 plus connecting my car radio...

I can calling, I can listen my music from iphone, I can use navigation with car radio. But whatsapp video and voice messagge are not working correctly.

worst of all, no sound is heard.

if I want to listen, I must to

-cut Bluetooth connection

then I can listen from my telephone...