i'm working on a facebook application using flask framework and i have a problem with facebook connect via oauth

here is the error msg that i got :
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.

i'm using heroku to host the app and i even tried locally and it does not work. can anyone help me ?