Sound problem with Icecast

Hi ! I am trying to set up Mopidy 2.0 with Icecast on a debian server. For the moment, it seems to work except I don’t have sound.:hushed:

When I select a song on spotmop interface and I go to the Icecast2 web page, I see the music that I am playing. If I click the m3u button, I can listen the streaming…

The only warning I receive is :

WARNING 2016-03-19 16:53:49,645 [17089:MainThread]
GStreamer warning: gst-stream-error-quark: No volume control found (3)

and this is the audio part in my config file:

mixer = software
mixer_volume = 100
output = lamemp3enc ! shout2send mount=mopidy ip= port=8000 password=donthackme
buffer_time =

I have no clue why it isn’t working. So any help would be greatly appreciated