using (WebClient webClient = new WebClient())
{
webClient.Encoding = Encoding.GetEncoding("utf-8");
webClient.Headers.Add("Content-Type", "application/json");
webClient.Headers.Add(HttpRequestHeader.Cookie, $@"{CookieName}={CookieValue}");//<------------------------------
byte[] responseData = webClient.UploadData(url, "POST", postData);
re = JsonConvert.DeserializeObject<JObject>(Encoding.UTF8.GetString(responseData));