Here's the report...Thanks for your help.
The report shows that the DMRA could successfully push the MP3 test track to the Sonos. You could also download the DMRA version with the full set of media test tracks, and test which other media formats will play.
As far as MC is concerned, I suggest setting the MC DLNA server to push audio in Original format. It should play WAV, FLAC and MP3 without problems.
(Note: the Sonos is one of the few renderers that I have seen that clearly does NOT support the L16 aka PCM No Header format. So for this lack, it earns the right to be named as a DLNA non compliant renderer..)
If the Sonos works with the DMRA test tracks, but not with MC, then you probably have a firewall or router problem that is blocking communications between MC and the Sonos.