diff --git a/testOauthClient/Controllers/HomeController.cs b/testOauthClient/Controllers/HomeController.cs
index a8588369..db43ac18 100755
--- a/testOauthClient/Controllers/HomeController.cs
+++ b/testOauthClient/Controllers/HomeController.cs
@@ -34,7 +34,7 @@ namespace testOauthClient.Controllers
             get {
                 var claim = HttpContext.User?.FindFirst("access_token");
                 if (claim == null) {
-                    throw new InvalidOperationException();
+                    throw new InvalidOperationException("no access_token");
                 }
 
                 return claim.Value;