Sharing on Facebook, Google, etc..

Hello

we are facing an issue with social sharing plugins, the site has the membership plugin installed and it the website cant be viewed until the person registers (free) ! after a person registers and logs in and try to share an article, on facebook for example it shows (registration message) not the article.. but on twitter it shows the title and link which is working fine !

Plugins Used to Share
Floating Social

please let us know whats the solution for facebook and google

Thanks