@lleclerc commented on @mrkozma’s file https://netsuiteprofessionals.slack.com/files/U679VC54Z/F6LB317T5/restsharp_call_to_netsuite.cs: Can you try with this code instead ? HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url); request.Method = "POST"; request.ContentType = "text/plain"; request.Headers.Add("YourHeader", "values"); using (Stream stm = request.GetRequestStream()) { using (StreamWriter stmw = new StreamWriter(stm)) { stmw.Write(soaprequest); } } WebResponse response = request.GetResponse(); Stream responseStream = response.GetResponseStream(); StreamReader sr = new StreamReader(responseStream); string result = sr.ReadToEnd();