The FAQ was referring to our
Common Support Questions
under the "What do these AUtotune Error Check errors mean?" topic. Here's the explanation for the error.
Error Code: 406 - Unknown Error - The full error coming back from Autotune is usually "Not Acceptable! An appropriate representation of the requested resource could not be found on this server. This error was generated by Mod_Security." It seems like mod_security (an Apache firewall addon) is blocking our automated tool from scanning your page. Mod_security, in general, tries to prevent 'bad' requests (malicious, automated, and various other kinds). It may be detecting our tool is automated (not a real browser) and denying it. You'll need to investigate your mod_security logs, or disable it, to let the Autotune tool perform its checks. Additionally, we recommend testing your page with other automated checkers, such as www.internetmarketingninjas.com/header-checker/
I just manually performed the checks on your site
www.karaokeacrossamerica.com and there were no problems that I saw. Unless you're having functional issues with your JFBConnect login / other functionality not working as expected, I would not worry about the warning.
-Melissa