M4A files not found/recognized

Hi,

I've been using LMS for a while on my x86 server running Debian 10. It works great. I use it to stream to various AirPlay and UPnP-compatible devices around the house.

However, I have the problem that I have m4a and mp4 files in my library and I would like to play those files, too. I have tried searching the forums and the web for a solution, but I didn't find any. The problem is that the folders with the m4a files will appear to be empty when I browse to them in the web interface or Squeezer (Android app). So it's likely that for some reason they are being ignored, and I don't know how to find out why and how to make LMS not ignore them.

Any pointers?

Thanks,

Stefan