Facebook Comment Box doesn't display


I enabled the "Use Facebook for comments" and "Override WordPress discussion settings" setting for the comments on my site. However, it doesn't display in there. I published a test post: http://boca-raton-fl.emergencydentalwalkins.com/2014/07/08/test/ to check if it appears on a fresh article, but still no luck. Am i missing something ? I'd be glad to hear some suggestions.