No OWIN authentication manager is associated with the request

Question

After trying to enable owin & AspNet Identity to my Web Api project (in VS 2013 + .Net 4.5.1) I get the following error in each valid or unvalid(request to none exist co

Answer 1

I had the same problem. The package was not appearing in the NuGet Package manager. I added reference in packages.config:

And reference in the project file (xxx.csproj):

 
  ..\packages\Microsoft.Owin.Host.SystemWeb.2.1.0\lib\net45\Microsoft.Owin.Host.SystemWeb.dll