No sound when streaming from no-sound-card server

I am trying to install Mopidy on my HP microserver g7 N54L. It is an headless server, without audio card then.
I get tracks to be read from the client so I guess it is streaming, but no sound. I have installed
I am using :
mixer = software
mixer_volume =
output = autoaudiosink
buffer_time =
With other parameters it just doesn’t work at all : no tracks being read from client.
Is the problem building the sound on the server ? I would like to avoid icecast because I use Flac and don’t want to lose sound quality.
What should I do to have sound when reading from client ?

You need to setup mopidy to output via icecast or snapcast or something so that you can then receive audio on a matching client on your other machine. Mopidy does not stream output to your web client by default.

Mopidy-Stream is installed. Isn’t that enough ?

Mopidy is a server that plays music locally. It is similar to mpd. When you run Mopidy on your machine it outputs using the local audio device on that machine. If you want to stream that output somewhere else then you need to use something like icecast and configure it as described in the docs. The HTTP/MPD clients available are really just remote controls.

Since your machine does not have a local audio device then you must use icecast/snapcast/whatever.

Mopidy-Stream is an extension for playing streaming music.

i.e. for playing online radio streams, not serving them.