If you try to integrate a Facebook page and it’s not working, be sure that:
1. You have filled out the Facebook API in your backoffice in Settings > APIs
2. You have entered your domain.com only in the Facebook app at https://developers.facebook.com in the field “App Domains”, and your subdomain (if installed on a subdomain) + http:// in the fields for website:
4. The Facebook fan page you integrate is “public”. Some Facebook pages, like the one for bars, clubs, and restaurants are not authorized for user under 18. It can’t be integrated because the data of the page are not shared by Facebook.