I'm getting an error when clicking the facebook button on my app . It works perfectly on my development system when I add a localhost on the website platform . But when I click the button on facebook canvas app it showing an error " 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." What should I do? What modifications I need to do my website. I'm hosting app on heroku.com