ASP.NET MVC5 OWIN Facebook authentication suddenly not working

Question

Update 2017!

The issue I had when I posted the original question has got nothing to do with the recent changes Facebook made when they forced everyo

Answer 1

Even though i did everything what sammy34 said, it did not work for me. I was at the same point with HaukurHaf: When i make apirequest manually on browser it works perfect, but if i use my mvc app, GetExternalLoginInfoAsync() always returns null.

So i changed some rows on sammy34's codes like on this comment: https://stackoverflow.com/a/43148543/7776015

Replaced:

if (!request.RequestUri.AbsolutePath.Contains("/oauth"))
{
request.RequestUri = new Uri(request.RequestUri.AbsoluteUri.Replace("?access_token", "&access_token"));
}
var result = await base.SendAsync(request, cancellationToken);
if (!request.RequestUri.AbsolutePath.Contains("/oauth"))
{
return result;
}

Instead of:

var result = await base.SendAsync(request, cancellationToken);
if (!request.RequestUri.AbsolutePath.Contains("access_token"))
return result;

And added this row into my FacebookAuthenticationOptions:

UserInformationEndpoint = "https://graph.facebook.com/v2.8/me?fields=id,name,email,first_name,last_name,picture"

and now it works.(fields and that parameters optional)

Note: I did not update Microsoft.Owin.Security.Facebook