Hi verclytte,

It seems like the single stream for the one that you want to share on Facebook was private(which non-login user cannot see it: http://take.ms/p5gYG ).Remember that you have to treat Facebook as a guest user as well. So if you cannot access the page as a guest, then FB will not be able to crawl the information too.

In order to make the stream item was share-able in the Facebook, the single stream should be in public view.

Hello,

I am well connected on the site cgpigroup.fr
I'm also logged in with my personal accounts on Facebook, twitter and Linkedin

The problem is despite all active

I do not understand your answer?

Hi verclytte,

Sorry, perhaps my explanation not really clear for you.
Basically, the stream item that in private (guest user cannot see/access http://take.ms/p5gYG ) all social share cannot get the correct image, description as it cannot crawl the data from your site

In other word, social share only can get the correct data when the single stream item was in public(everyone can see).

Or I can parameterize that guest them to see the elements of the flow of the groups?

Hi verclytte,

Yes, you can just change the single stream item to be in public view http://take.ms/ZN5z6 and the group was in open group