diff --git a/websocket-sharp/Net/HttpListener.cs b/websocket-sharp/Net/HttpListener.cs
index abb3e344..2c5857b5 100644
--- a/websocket-sharp/Net/HttpListener.cs
+++ b/websocket-sharp/Net/HttpListener.cs
@@ -809,8 +809,8 @@ namespace WebSocketSharp.Net
         return;
 
       _listening = false;
-
       EndPointManager.RemoveListener (this);
+
       lock (_ctxRegistrySync)
         sendServiceUnavailable ();