I have installed this plugin on my Synology 916+ in

/usr/local/domoticz/var/plugins/domoticz-sonos

and it's working

Your file permissions are wrong. Set permissions for plug-in.py file to 0777

Thanks to you both!!!

Changed the rights and owner of the files/folders, and moved everything ...

Hey!
I have a Synology DS1515+ NAS with DSM version 6.1-15047.
And I have installed Domoticz Beta v3.7320 by jumbotroll, that should support Python Plugin Beta.
The problem is that when I add plugins, Sonos , the Domoticz installation can't find it.

The logs from Domoticz startup is:
2017-04-17 ...