You will need to create an app on the Facebook developers portal (https://developers.facebook.com) in order to use Facebook features, these can be linked with MyAppBuilder by filling out the API settings in the editor.
You need to assign the “Valid OAuth redirect URIs” to the three URL’s bellow
http://localhost/ – http://localhost/callback – http://apps.webmateapps.com/
Click on the icon represents your apps project. This will open your apps project dashboard.
Click on “Settings” below the “Dashboard”.
Click on “Advanced” tab and scroll down and look for “Client OAuth Settings”.
Leave that “Client OAuth Login” and “Web OAuth Login” in status: Yes.
And leave that “Embedded Browser OAuth Login” and “Force Web OAuth Reauthentication” in status: No.
Under “Valid OAuth redirect URIs” enter: apps.webmateapps.com
Lastly, switch the “Login from Devices” to status: Yes.
Scroll down and “Save Changes”.
Please Reload your Apps and it should fix the Facebook Login.