为什么我不能在agsXMPP中连接到googletalk?

agsXMPP ,但我有一些问题。我正在尝试运行以下代码:

using System;
using agsXMPP;

namespace TestAgs
{
    class MainClass
    {
        public static void Main (string[] args)
        {
            XmppClientConnection connection = new XmppClientConnection ();
            connection.OnLogin += delegate {
                Console.WriteLine ("logged in");
            };
            connection.Server = "gmail.com";
            connection.ConnectServer = "talk.google.com";
            connection.Username = "my username"; // I tried both with and without '@gmail.com'
            connection.Password = "my password";
            connection.Open();
        }
    }
}