WebService异常——底层连接已关闭:发送时发生意外错误

我已经编写了下面的方法来从客户端web服务检索XML响应。在下面的代码中，我收到的错误为{"无法从传输连接读取数据:远程主机强制关闭了现有连接。"}

请帮助。

下面代码错误

WebResponse webResponse = req.GetResponse();  

调用WebService的方法-

[WebMethod]
public XmlDocument GetData()
{
    string sError = "";
    string sApiSession;
    DateTime dtRequested = DateTime.Now;
    XmlDocument xmlDoc = new XmlDocument();
    XDocument xDoc = new XDocument();
    try
    {
        NetworkCredential creds = new NetworkCredential();
        creds.UserName = System.Configuration.ConfigurationManager.AppSettings.Get("UserName");
        creds.Password = System.Configuration.ConfigurationManager.AppSettings.Get("Password");
        WebRequest req = WebRequest.Create(System.Configuration.ConfigurationManager.AppSettings.Get("Services"));
        req.Method = System.Configuration.ConfigurationManager.AppSettings.Get("Method");
        req.ContentType = System.Configuration.ConfigurationManager.AppSettings.Get("ContentType ");
        req.Credentials = creds;
        //Retriev into webresponse
        WebResponse webResponse = req.GetResponse();
        //Read from WebResponse to datastream
        Stream dataStream = webResponse.GetResponseStream();
        //read the content of data stream
        using (StreamReader reader = new StreamReader(dataStream))
        {
            xDoc = XDocument.Load(reader);
        }
    }
    catch (Exception ex)
    {
        throw;
    }
    return xmlDoc = getXml(xDoc);
}    

我已经点击了下面的链接，但仍然没有结果。

http://briancaos.wordpress.com/2012/06/15/an-existing-connection-was-forcibly-closed-by-the-remote-host/