Recording instastory while aux cable is on

Hello

I hope all is well with you guys.

I had an iPhone 12, and I could listen/play music in my car via an aux cable and simultaneously record a video with audio and post it on my Instastory without any issue. The sound was on in the video.

Now I upgraded to iPhone 15 Pro, and I can't record video with audio while listening/playing music from my aux cable. Do you have any idea why? I mean the video has no audio in it . I tried it with my iPhone 12, but it still works perfectly, unlike the iPhone 15.

Many thanks for any help you can provide.