c# web

Question

im trying to send data, to server, at first attempt it sends successful but at second, it stuck or quits with an error "timeout" the error occurs in line : postdt = WebReq1.GetRequestStream(); the program: buff = Encoding.ASCII.GetBytes(""); WebReq1 = (HttpWebRequest)WebRequest.Create("http://"); WebReq1.Method = "POST"; WebReq1.ContentType = "application/x-www-form-urlencoded"; WebReq1.ContentLength = buff.Length; WebReq1.CookieContainer = WebReq.CookieContainer; postdt = WebReq1.GetRequestStream(); postdt.Write(buff, 0, buff.Length);