I tried to place Facebook Login App on two places on my website. Now the app is no longer working. The message is as follows:
Given URL is not allowed by the Application configuration.: One or more of the given URLs is not allowed by the App’s settings. It must match the Website URL or Canvas URL, or the domain must be a subdomain of one of the App’s domains.
There is a Facebook community page with several answers on this, please see http://www.facebook.com/help/community/question/?id=542958419109491
Also try https://github.com/facebook/facebook-php-sdk