I have correctly linked my Sonos Controler to Plex and followed what is written here :
Well, now, when I try to browse Plex from Sonos, I have this message after a few seconds :
FR Unable to contact the Plex Media Server. Please check your server settings at https://plex.tv and make sure that Remote Access is enabled.
So, YES, the remote access has been enabled.
But I have declared users on Plex (to filter the movies my young daughter could access to). Could it be why I have this issue ? There is nowhere to set a default user in Plex for Sonos...
Many thanks for your help !