NullReferenceException with Owin
I've just cloned a project to a new machine and I'm getting a hard-to-debug NullReferenceException on a MVC site with OWIN: [NullReferenceException: Object reference not set to an instance of an object.] Microsoft.Owin.Security.Cookies.<AuthenticateCoreAsync>d__0.MoveNext() +664 System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task) +93 System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task) +52 System.Runtime.CompilerServices.TaskAwaiter`1.GetResult() +24 Microsoft.Owin.Security.Infrastructure.<BaseInitializeAsync>d__2.MoveNext() +860