Track is not playable

[artelse]

Trying to use mopidy-beets-local. I fixed some python 2/3 issues, but got stuck on below problem.
The file plays through gst without problems:
gst-launch-1.0 playbin uri=file:///volume1/audio/_audio2sort/MP3/claris.mp3

Running mopidy 3.0.2 and beets 1.5.0.

ERROR    2020-07-29 01:32:35,230 [10547:MainThread] mopidy.audio.gst
GStreamer error: Could not open resource for reading.
WARNING  2020-07-29 01:32:35,257 [10547:Audio-2] mopidy.audio.actor
Setting GStreamer state to GST_STATE_PLAYING failed
WARNING  2020-07-29 01:32:35,258 [10547:Core-4] mopidy.core.tracklist
Track is not playable: beetslocal:track:13:b'/volume1/audio/_audio2sort/MP3/claris.mp3'