I'm trying to get access token from user
string response_script = "<script>top.location.href='https://www.facebook.com/v2.4/dialog/oauth?response_type=token&client_id=[APPLICATION ID]&redirect_uri=https://www.facebook.com/[APPLICATION URL]/?sk=app_[PAGE ID]&scope='; </script>";
Can't Load URL: The domain of this URL isn't included in the app's domains. To be able to load this URL, add all domains and subdomains of your app to the App Domains field in your app settings.
Valid OAuth redirect URIs
I had the same issue as you, I figured it out. Facebook now roles some features as plugins. In the left hand side select Products and add product. Then select Facbook Login. Pretty straight forward from there, you'll see all the Oauth options show up.