If you've updated the URL structure on your site, even just adding the ability to use https, you'll need to update each social network application to expect those new URLs. For Google, please look through our setup guide:
www.sourcecoast.com/jfbconnect/docs/soci...le-application-setup
Specifically, step 7-b-vi which specifies the valid Redirect URIs that Google should allow.
I hope that helps,
Alex