https://xenforo.com/help/facebook/ The text "Creating a Facebook Application" is not correct because there has been an update to Facebook. The problem is the URL in the app. Facebook changed their user interface for developer apps, so this can be tricky to find. Click Apps and then select your app. Click the Settings button on the left side of the screen. In the Basic settings, click the Add Platform button below the settings configuration. Select Website in the platform dialog. Enter your URL (localhost works here). In the App Domains text input, add your domain that matches the one in the URL. Save your settings.