System.NullReferenceException: Object reference not set to an instance of an object.
   at RealGrader.Web.Instacard.ManifestJsonMiddleware.Build(HttpContext context, String alias, String version) in E:\vivendi.visualstudio.com\GIT\RealGrader.Core\RealGrader\RealGrader.Web.Instacard\ManifestJsonMiddleware.cs:line 75