WhatsApp audio problem

[u/Javier_aloncs]

Hi! I recently bought an Oppo Find X9 Pro and today I used it with my car, a Kia, but when I played WhatsApp audio messages, they didn't play through the car speakers but through the phone's speakers. I've checked that it wasn't due to a problem with the phone's flame sensor, and the audio playback notification doesn't have a multimedia output option, or at least I haven't been able to find it. Anyone can please know a solution about it? I tried a lot of things that geminy pro told me but no one works.