Соединение через Proxy (httpwebrequest) и ошибка "Не удалось создать защищенный канал SSL/TLS"

        public static bool AcceptAllCertificatePolicy(object sender, X509Certificate certificate, X509Chain chain, System.Net.Security.SslPolicyErrors sslPolicyErrors)
        {
            return true;
        }
 
        private void button4_Click_2(object sender, EventArgs e)
        {
           HttpWebRequest myHttpWebRequest = (HttpWebRequest)HttpWebRequest.Create("https://*******.com");
            string sCookies = GetCookie();
            myHttpWebRequest.ServicePoint.Expect100Continue = false;
            myHttpWebRequest.Proxy = new WebProxy("ipproxy", port);
            myHttpWebRequest.Method = "GET";
            myHttpWebRequest.Referer = "*******";
            myHttpWebRequest.UserAgent = "Mozilla/5.0 (Windows NT 5.1; rv:12.0) Gecko/20100101 Firefox/12.0";
            myHttpWebRequest.Accept = "text/html, application/xml;q=0.9, application/xhtml+xml, image/png, image/webp, image/jpeg, image/gif, image/x-xbitmap, */*;q=0.1";
            myHttpWebRequest.Headers.Add("Accept-Encoding", "gzip, deflate");
            myHttpWebRequest.Headers.Add("Accept-Language", "en-US,ru;q=0.8,en-us;q=0.5,en;q=0.3");
            myHttpWebRequest.KeepAlive = true;
            ServicePointManager.ServerCertificateValidationCallback += AcceptAllCertificatePolicy;
 
            if (!String.IsNullOrEmpty(sCookies))
                myHttpWebRequest.Headers.Add(HttpRequestHeader.Cookie, sCookies);
                myHttpWebRequest.AllowAutoRedirect = false;
 
 
            //тут получаем ответ
                HttpWebResponse response = (HttpWebResponse)myHttpWebRequest.GetResponse();
 
                Stream responseStream = responseStream = response.GetResponseStream();
                if (response.ContentEncoding.ToLower().Contains("gzip"))
                    responseStream = new System.IO.Compression.GZipStream(responseStream, System.IO.Compression.CompressionMode.Decompress);
                else if (response.ContentEncoding.ToLower().Contains("deflate"))
                    responseStream = new System.IO.Compression.DeflateStream(responseStream, System.IO.Compression.CompressionMode.Decompress);
 
 
                StreamReader reader = new StreamReader(responseStream, Encoding.GetEncoding("UTF-8"));
                string resp = reader.ReadToEnd();
                response.Close();
}

                HttpWebResponse response = (HttpWebResponse)myHttpWebRequest.GetResponse();

            myHttpWebRequest.Credentials = CredentialCache.DefaultCredentials;