No sound / MPD error (moode 8.2.0 / Allo BOSS / RPI 3 B+)

[wasbaer]

Hello everybody!
Can someone please help?

On a fresh install, I keep getting this error when trying to play music.

Code:

MPD error: Failed to open "ALSA Default" (alsa); Failed to open ALSA device "_audioout": No such file or directory

moode 8.2.0 / Allo BOSS / RPI 3 B+

What do I need to do?

Please tell me what kind of info you need to identify the problem.
I'm most grateful for your time.
Thanks!