I hope I find a answer here. So far I've managed to install mopidy and configure a local USB drive to be accessible via the Musicbox webclient. So far so good.
My Raspberry has a Hifiberry DAC installed on it (not die Dac+ version)
I've just tested the general functionality of the DAC and it works fine, playback of a WAV file was successfull.
It is visible via aplay -l:
**** List of PLAYBACK Hardware Devices ****
card 0: sndrpihifiberry [snd_rpi_hifiberry_dac], device 0: HifiBerry DAC HiFi pcm5102a-hifi-0 
Subdevice #0: subdevice #0
My audio output is set to:
output = hifiberry_dac
When starting the service via sudo service mopidy start it always fails at the audio output which shows the following error.
Apr 15 20:51:00 raspberrypi mopidy: ERROR Failed to create audio output "hifiberry_dac": gst_parse_error: no element "hifiberry_dac" (1)
I really don't have any idea what I have to change to make this working...
Please tell me what additional information you need to troubleshoot this. At least the DAC is working fine but I couldn't manage to get it running with mopidy.