I've developed an app receiving notifications by the server and playing an audio file included in the app itself. The app is working fine but I've a customer with an Alcatel 5033X - Android 8.1.0 terminal who is receiving notifications but his phone doesn't play the audio file.
What I can see is that the device hasn't a predefined audio app: there is not an audio category at all within predefined apps. I'm wondering if this could be the problem and eventually how I could add a predefined audio app to the system.
Any other idea would be very welcome.