diff --git a/websocket-sharp/Net/HttpListener.cs b/websocket-sharp/Net/HttpListener.cs
index 1a62307a..9a5ad839 100644
--- a/websocket-sharp/Net/HttpListener.cs
+++ b/websocket-sharp/Net/HttpListener.cs
@@ -574,8 +574,7 @@ namespace WebSocketSharp.Net
 
     internal Func<IIdentity, NetworkCredential> GetUserCredentialsFinder ()
     {
-      var finder = _userCredFinder;
-      return finder ?? (id => null);
+      return _userCredFinder;
     }
 
     internal bool RegisterContext (HttpListenerContext context)