error: blank page

Those are 2 separate issues. For the first (the login issue), check the following:
1) Unpublish any JFBCProfile plugins that you don't have the extension installed for. So, if you have the JomSocial extension installed, don't publish the JomSocial profile extension, etc.
2) If the profile extensions you have are correct, enable Error Reporting, and let us know what error shows up on that blank page. That will help us diagnose the problem quickly. To enable error reporting, see:
www.sourcecoast.com/extensions/troublesh...ng-joomla-extensions

For the invite module, it's likely the "Thank you" URL parameter you have setup in the module's parameters is simply pointing to an invalid page. Please make sure this page exists and works on your site (try going to it directly) and make sure that in Joomla it's marked as "Public" and if it's a content page, that the article is published.

Hope this helps get you started, but if you gather more information from the above, let us know and hopefully we can get you further along.

When I go to that page that you linked, I get the below, which doesn't seem to be valid:
404 - Componente non trovato

Can you try visiting that link when you aren't logged in? The JFBCInvite module has no way to check if the user is able to see the destination page, we just redirect them to wherever you put in that box. Once you get that link working (or use a different one), things should work as expected.

Glad we got you going on the first issue though, and let us know if you get the Invite module setup right or if you continue to have problems.

I couldn't find the Invite module on your page. Can you send me a link to the page it's published on? Mainly, I want to test and see the page you're redirected too, because something's obviously strange. If it's redirecting to the URL you specify above, I don't know why there would be an issue. My guess is that it's going somewhere else, but not sure where.. or why.

Either way, we'll get you fixed up

Thanks for posting the link. I just tired and was able to see the problem. However, it looks to be a server issue, not anything with JFBConnect. I think there's some functionality on your site that's preventing redirects or referrals from Facebook (or other pages). Some security suites prevent these types of redirects because they can be used for nefarious purposes.

Unfortunately, I don't think there's much we can do on our end because it's definitely an Apache page that's spitting out the error. That happens well before Joomla (or JFBConnect) does anything. You can try with the Thank You page being your home page, but I think you'll still run into the same problem.

Good luck!