Address is Invalid Error in Safari

When I am clicking on the ‘Login with Facebook’ link in the application, it automatically goes to Safari and asked for authorization of the application. But when I am clicking on ‘Allow’, it is not directing to Facebook page and an alert is coming which says “The page cannot be opened on Safari as the address is invalid.” I think there is no problem with my iPhone application but may be a problem with Facebook settings. I am not sure this is the problem. So please help me. Thanks in advance.
