由于目标机器主动拒绝连接，所以无法连接？

Question

由于目标机器主动拒绝连接，所以无法连接？

有时，当我对WebService执行HttpWebRequest时，会收到以下错误。下面我也复制了我的代码。

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ServicePointManager.CertificatePolicy = new TrustAllCertificatePolicy();HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
request.PreAuthenticate = true;request.Credentials = networkCredential(sla);request.Method = WebRequestMethods.Http.Post;
request.ContentType = "application/x-www-form-urlencoded";request.Timeout = v_Timeout * 1000;
if (url.IndexOf("asmx") > 0 && parStartIndex > 0){
    AppHelper.Logger.Append("#############" + sla.ServiceName);

    using (StreamWriter reqWriter = new StreamWriter(request.GetRequestStream()))
    {                        
        while (true)
        {
            int index01 = parList.Length;
            int index02 = parList.IndexOf("=");

            if (parList.IndexOf("&") > 0)
                index01 = parList.IndexOf("&");

            string parName = parList.Substring(0, index02);
            string parValue = parList.Substring(index02 + 1, index01 - index02 - 1);

            reqWriter.Write("{0}={1}", HttpUtility.UrlEncode(parName), HttpUtility.UrlEncode(parValue));

             if (index01 == parList.Length)
                 break;

             reqWriter.Write("&");
             parList = parList.Substring(index01 + 1);
         }
     }
 }
 else
 {
     request.ContentLength = 0;
 }

 response = (HttpWebResponse)request.GetResponse();