Hello Guys.
I have tried searching and didn't find any solution regarding it. Please have a look at this URL.
https://apps.facebook.com/345755845824984
It's a multiplayer game that I have made using Unity Photon Plugin for PlayFab. The game works fine on Android and iOS but for Facebook as you guys know, we need to put all URL that are being accessed in the app in the Developer console. Or Facebook will throw errors and won't allow to move on.
Please see the screen shot of field where I need to put app Domain URL
also please check the error message.