New Post: Remote shutdown PC

I have a router installed pfSense, IP 192.168.254.3.
I wan to shutdown it from a windown pc. I code by C#. Here my code:

    private void btnShutdown_Click(object sender, EventArgs e)
    {
           var sshcln = new Renci.SshNet.SshClient("192.168.254.3", 22, "admin", "pfsense");
           if (sshcln.IsConnected == false)
           {
               sshcln.Connect();
               Renci.SshNet.SshCommand cmd;                               
               cmd = sshcln.CreateCommand("shutdown -p now"); //Shutdown command
               cmd.Execute();
               sshcln.Disconnect();                
           }
     }

It was connected to 192.168.254.3. but nothing happened.
I tried change some others format of command text such as "poweroff". "admin@192.168.254.3 shutdown -p now", "ssh poweroff"

Please help me. Thanks