diff --git a/websocket-sharp/Server/WebSocketSessionManager.cs b/websocket-sharp/Server/WebSocketSessionManager.cs
index 50227ba7..74c81c08 100644
--- a/websocket-sharp/Server/WebSocketSessionManager.cs
+++ b/websocket-sharp/Server/WebSocketSessionManager.cs
@@ -228,13 +228,8 @@ namespace WebSocketSharp.Server
 
       set {
         lock (_sync) {
-          string msg;
-
-          if (!canSet (out msg)) {
-            _log.Warn (msg);
-
+          if (!canSet ())
             return;
-          }
 
           _keepClean = value;
         }