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

Noticed this problem yesterday. Facebook does not support Microsoft.Owin.Security.Facebook version 3.0.1 anymore. For me it worked to install version 3.1.0. To update to 3.1.0, run the command Install-Package Microsoft.Owin.Security.Facebook in Package Manager Console: https://www.nuget.org/packages/Microsoft.Owin.Security.Facebook