public static DataSet PostData_PurpleAPITxnStatus1(Credentials crd, string Url, string MethodName, string JsonRequest, string SessionToken, string SoapAction = null, string ContentType = null, string EntireSopaAction = null, string Product = null, string Param1 = null, string Param2 = null, string Param3 = null, string Allow = null)
{

        string Folderpath = ConfigurationManager.AppSettings["logpath"].ToString();
        Folderpath = Folderpath + "\" + Product + "\" + System.DateTime.Now.ToString("dd-MM-yyy") + "\" + Param1 + "\";

        if (!Directory.Exists(Folderpath))
            Directory.CreateDirectory(Folderpath);
        HttpWebRequest webrequest = null;
        HttpWebResponse resp = null;

        var requestInterceptor = new SymexInspector();
        xmlSymexFileWriter xmlwrite = new xmlSymexFileWriter();
        Random RandomNumber = new Random();
        //var requestDataBytes = "";
        DataSet ds = new DataSet();
        string apiUrl = "https://api.test.purplme.com/remittances/131/";
        string ResponseData = string.Empty;

        string resulXmlFromWebService = string.Empty;
        string AuthHeader = SessionToken;

        try
        {
            ServicePointManager.Expect100Continue = true;
            // ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls | SecurityProtocolType.Ssl3 | (SecurityProtocolType)3072 | (SecurityProtocolType)768 | SecurityProtocolType.Tls12;
            ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls11 | SecurityProtocolType.Ssl3 | SecurityProtocolType.Tls12;
            ServicePointManager.ServerCertificateValidationCallback = delegate { return true; };

            webrequest = (HttpWebRequest)WebRequest.Create(apiUrl);
            webrequest.Method = "GET";                    
            webrequest.Headers["Authorization"] = "Bearer " + AuthHeader;
            webrequest.ContentType = "application/json";              

            resp = (HttpWebResponse)webrequest.GetResponse();

            using (StreamReader reader = new StreamReader(resp.GetResponseStream()))
            {
                ResponseData = reader.ReadToEnd();

            }



            resp = (HttpWebResponse)webrequest.GetResponse();

            using (StreamReader reader = new StreamReader(resp.GetResponseStream()))
            {
                ResponseData = reader.ReadToEnd();

            }

           
        }
        #region ErroCatch
        catch (WebException webex)
        {
            string Response = "";
            WebResponse response = webex.Response;
            if (response == null)
            {
                 string ResponseXml = ("<Response><ErroCode>-99</ErroCode><ErroDesc>" + webex.Message.ToString() + "</ErroDesc></Response>");
                StringReader srError = new StringReader(ResponseXml);
                ds.ReadXml(srError);

            }
            else
            {

                using (response = webex.Response)
                {
                    HttpWebResponse httpResponse = (HttpWebResponse)response;
                    using (Stream data = response.GetResponseStream())
                    using (var reader = new StreamReader(data))
                    {
                        Response = reader.ReadToEnd();
                    }
                }

                string Resp = ReadDataFromJsontoXml(Response);

                StringReader srs = new StringReader(Resp);
                ds.ReadXml(srs);
                
            }
        }
        catch (XmlSchemaInferenceException XmlException)
        {
            xmlwrite.WriteXml(JsonRequest, XmlException.Message.ToString(), Folderpath, string.Empty, string.Empty, Param1.Substring(0, 3) + System.DateTime.Now.ToString("ddMMMyyyyhhmmss") + "_" + ((Param3.Length == 0) || (Param3 == null) ? "0" : Param3.ToString()));
            StringReader sr = new StringReader(resulXmlFromWebService);
            ds.ReadXml(sr, XmlReadMode.ReadSchema);
        }
        catch (Exception ex)
        {

            xmlwrite.WriteXml(JsonRequest, ex.Message.ToString() + " " + ex.StackTrace.ToString(), Folderpath, string.Empty, string.Empty, Param1.Substring(0, 3) + System.DateTime.Now.ToString("ddMMMyyyyhhmmss") + "_" + ((Param3.Length == 0) || (Param3 == null) ? "0" : Param3.ToString()));
            string ResponseXml = ("<Response><ErroCode>-99</ErroCode><ErroDesc>Exception while Posting the data...</ErroDesc></Response>");
            StringReader srError = new StringReader(ResponseXml);
            ds.ReadXml(srError);
        }
        #endregion

        return ds;
    }

The above code returns 404 error from API but in postman its working fine