Redirect issue in codeigniter with using tank auth social
Your Facebook application "owns" by default the canvas url http://apps.facebook.com/your_app, but also a given domain which you have to enter. The redirect_uri is for security reasons only able to redirect you to either.
If you're unable to make this work, you can have the redirect_uri to point to a site such as http://apps.facebook.com/my_redirect and simply have controllers/my_redirect.php's index function to echo <script>top.location = 'http://google.com'</script> for example.
Regardless, check your settings in your application, and read up on these errors more since a lot people have posted them and gotten answers for them aswell.
you have to set your application URL in facebook application settings
Given URL is not allowed by the Application configuration.