Invalid Controller - JFB does not work anymore for me

There's some SEF issue that's causing this problem. Facebook is returning the user to the following link:But then something on your site is redirecting the user to an SEF URL that looks like:I'm not sure why that updated link isn't working, but you'll want to disable SEF URLs for JFBConnect in whatever SEF extension you're using to fix that problem.

I hope that helps, but if you need anything else, please give us as many details as you can on the SEF extension you're using and what happens if you disable SEF URLs altogether.

Thanks,
Alex