Could you let me know the specific URL where you're trying to log out from? I created a user on your page with my FB credentials, but don't see our login module anywhere on the page. The SCLogin module has a setting in the parameters > Logout View Settings > "Joomla Logout Redirection URL". Please make sure that this is set to the correct value. Additionally, check that the value for Login View Settings > 'Encrypt Login Form' is set to No.
If you're not using SCLogin to log out, please provide more detailed steps so that I can reproduce the problem on your page.
Thanks
-Melissa
Error logout redirection https
