无法从XMPP服务器获取花名册列表

我在https://www.blah.im用于测试目的。我使用agsXMPP客户端库与服务器进行通信。连接已通过身份验证，成员已登录。但不会显示花名册。

这是我的代码

xmpp.Open(userName, password);
    xmpp.OnLogin += new ObjectHandler(xmpp_OnLogin);       
    Console.WriteLine(xmpp.XmppConnectionState);
    Console.WriteLine("Authenticated {0},", xmpp.Authenticated);   
  Console.WriteLine("Wait"); 
      int i = 0;  
      do {
       Console.Write(".");
       i++;
       if (i == 10)
           _wait = false;
       Thread.Sleep(3000);   
     } while (_wait);

Console.WriteLine("Connection state   {0}", xmpp.XmppConnectionState);
Console.WriteLine("Authenticated {0},", xmpp.Authenticated);
 agsXMPP.protocol.client.Presence p =
 new agsXMPP.protocol.client.Presence
(ShowType.chat, "Online");
 p.Type = PresenceType.available;
  xmpp.Send(p);
    xmpp.OnPresence += new agsXMPP.protocol.client.PresenceHandler(xmpp_OnPresence); 
     Thread.Sleep(3000);
     Console.WriteLine("Who do you want to connect ");
      string friend = Console.ReadLine();   
       Console.WriteLine("Start Chat");

static void xmpp_OnPresence(object sender, agsXMPP.protocol.client.Presence pres)
   {
          Console.WriteLine("Available Contacts: ");
          Console.WriteLine("{0}@{1}  {2}", pres.From.User, pres.From.Server, pres.Type);
          Console.WriteLine();
    }

有没有什么订阅的事情必须做才能获得可用的会员？