diff --git a/websocket-sharp/Net/ClientSslConfiguration.cs b/websocket-sharp/Net/ClientSslConfiguration.cs
index 800bcb30d..3a3b3d431 100644
--- a/websocket-sharp/Net/ClientSslConfiguration.cs
+++ b/websocket-sharp/Net/ClientSslConfiguration.cs
@@ -64,7 +64,7 @@ public class ClientSslConfiguration
     /// </summary>
     public ClientSslConfiguration ()
     {
-      _enabledSslProtocols = SslProtocols.Default;
+      _enabledSslProtocols = SslProtocols.None;
     }
 
     /// <summary>
@@ -77,7 +77,7 @@ public ClientSslConfiguration ()
     public ClientSslConfiguration (string targetHost)
     {
       _targetHost = targetHost;
-      _enabledSslProtocols = SslProtocols.Default;
+      _enabledSslProtocols = SslProtocols.None;
     }
 
     /// <summary>