Plugin does not share Image to Facebook

I have connected my blog to 3 different facebook accounts (two people and one page). When I publish a post on my blog the plugin shares it to all three FB accounts but it does not include the post image. The image is inside the post and also declared as “preferred image” . Why??

See the post “Golf club dei giovani” as example here: https://www.facebook.com/pages/Anna-Ravinetto/272800509411282

http://ww.wp.xz.cn/plugins/social/