ASP.Net MVC: facebook logged in user's email is not coming

Question

i am using asp.net mvc 5. when i log in to facebook then i am redirect to page called ExternalLoginCallback there a textbox comes where i ask to put user email but i believe i should get fb logged in user's email automatically but nothing such coming. here is screen shot


i just add these line of code for facebook auth.

app.UseFacebookAuthentication(new FacebookAuthenticationOptions()
{
AppId = "222222222222222222",
AppSecret = "sssssssssssssssssss",
Scope = { "email" },
Fields = { "name", "email" }
});

anyone can tell me what kind of mistake i have made for which email is not coming in my case.

looking for a help. thanks