Yes, there's no og: image, but there's an image of a girl and you join page has image of a green creater, those image are shared. 

just ask to get the plugin reinstalled and you will see that the default image from the plugin is now the og image on hoin page

im  not talking about share anything

forget share it has nothig to do with it

Everything works properly and I still don't understand what the proble is, the plugin won't be reinstalled and it works properly just like it should be

i have show u so many times its not working

if the plugin was working like it says in the admin page any page that does not have a og image   is profile pages photos pages etc have  the image as og image
any other pages that dont have a og image ie join page should show the default image from the share plugin

my site i have reverted back to 1,7,5 plugin now and its working like the demo

,4 sorry
tomorow il get the update and i show u screen shots of after i update it how it still works like the demo
then il reinstall it and show u that it is then working on join page