No mp3 playback in android app NCP

Hello community,
My name is Rico and I’m pretty new to the cloud business and need your help. I hope I’ve come to the right place.

I have built an NCP on a raspi 4 and so far everything works quite well.
Except the mp3 playback in the android app with the internal player. Streaming via apps like Vlc doesn’t work either.
The player displays the message “The internal player cannot play the media file”. The streaming function, e.g. via VLC, does not work at all. No app is displayed here.
For videos such as mp4, both the internal player and streaming via VLC work perfectly.
In the web browser, mp3 files are also played perfectly. In a test cloud that was created on the PC, the mp3 files ran in the Android app. Seems to have something to do with the configuration of the Raspberry. Only the internal player is installed. No other apps.

Do you have any idea what this could be? Does anyone else have this problem?

Versions:
Samsung S21
One UI 6.1
Android 14
NC App 3.29.1
NCP web 28.0.5.1
NCP config v1.54.2
OS Armbian 24.5.1 bookworm
Linux 6.6.31
PHP 8.1.29

With a
Samsung S9
Android 10
One Ui 2.5
It doesn’t work either…

Many thanks in advance.

Greetings Rico

Hi, mp3 playback works fine for me out of the box.
Maybe have a look at logs from your server when requesting playback.
Server logs can be found List of Logs on NCP

Thanks for the reply, but I need more detailed instructions on what to look for and how to get there. I lack a bit of specialist knowledge. Sorry
THX