diff --git a/websocket-sharp/Server/WebSocketServer.cs b/websocket-sharp/Server/WebSocketServer.cs
index 6607e7d5..ea7416a5 100644
--- a/websocket-sharp/Server/WebSocketServer.cs
+++ b/websocket-sharp/Server/WebSocketServer.cs
@@ -1307,7 +1307,7 @@ namespace WebSocketSharp.Server
     /// </remarks>
     /// <exception cref="InvalidOperationException">
     ///   <para>
-    ///   There is no server certificate for secure connections.
+    ///   There is no server certificate for secure connection.
     ///   </para>
     ///   <para>
     ///   -or-