I was just able to create a user successfully on your page with my LinkedIn account. I also logged out and was able to log back in with no errors. You should be able to see my user in the JFBConnect usermap area.
That being said, I can't find a big block of code that we're normally inserting into the page. It appears that you have JCH Optimize turned on again? I'd suggest disabling it again and running Autotune again to see if the errors persist.
Since it worked for my user, do you have any channels set up in the backend with the user you're logging in with as the channel owner? Perhaps there's a permission request happening that could be related. Have you tried logging in with a different LinkedIn user?
-Melissa