I’ve been using mopidy with spotify for a couple of years now. But since this morning MPC and my web client both say that a song is playing. Even when I go to the next. But all of a sudden the sound is gone. I mean mopidy says it’s playing. But I can’t hear it. When I play a sound with mplayer on the same Pi. It works okay.
Any idea where to look for?
Really no one? It is really playing. But it no longer sends music to the sound device. When I play a spotify list, my spotify client on my laptop stops playing. So it must be playing. But no sound 
What could suddenly have stopped working after almost a year? I have no clue where to look for, so help is truly welcome. Christmas is coming soon, so I have to explain to my kids that they won’t be listening to Christmas music this year.
You are right, software doesn’t suddenly stop working. Did you update your system recently? Please. Post the output of mopidy deps. A debug log might be helpful too. There is a troubleshooting page in the docs you could read.
Also, you say the ‘volume is suddenly down’ but presumably the volume number doesn’t actually suddenly change to zero, right? It’s a case of no audio being played, yeh? That’s an important difference.
I haven’t updated the system for a couple of months. I came across a thread on github where someone set mixer=None and now I can hear local files again. So I have to check if I can get it working again from that point.
The volume level was never 0, I’ve written a MQTT websocket bridge a year ago. That sends volume changes to a mqtt topic. Works great, but als says the volume is 40 and changes when I change the volume with MPC
But still very strange. I’ll check how I can get the debug log to work and post back.
Okay don’t ask how. But it’s working again. When I put mixer=None in the audo section of the config I could play local music again. I removed that line - commented it - and now everything works again.
Maybe the volume was set to zero after each reboot of mopidy? I have the setting for remembering the playback settings. Strange. But it works again. Thanx for your time.