The Subscription is limited to logged in users

Leo,
First, I tried to test on your page, but when I did, the following error from Facebook appeared:

This app is in sandbox mode. Edit the app configuration at developers.facebook.com/apps to make the app publicly visible.

To fix, please go into your Facebook Developer Area and set "Sandbox Mode" to "disabled".

As for the issue you mentioned, I'm not sure what could be causing that without seeing the problem happen. The things I'd check are:
* You don't have any User Plugins that are trying to redirect the users on login
* You don't have any User or Authentication plugins that are validating something else about the user, like a user group level
* You are being properly redirected to the JFBConnect Login/Register page and not a different registration page, which may not work the same as ours.

I hope that helps get you started, but if not, let us know and we'll gladly investigate further.. once Sandbox mode is disabled.

Thanks,
Alex