question

This is my code.I made a public sandbox account.Geting an error 401 unauthorized.

  var httpWebRequest = (HttpWebRequest)WebRequest.Create(" https://platform.devtest.ringcentral.com/restapi/oauth/authorize");
               
                httpWebRequest.Method = "GET";

                httpWebRequest.Headers.Add("client_id", "DShb1**********2DlM5xoA");
                httpWebRequest.Headers.Add("redirect_uri", " http://localhost:505471/");
                httpWebRequest.Headers.Add("response_type", "code");
                httpWebRequest.Headers.Add("state", "Client state");
                httpWebRequest.Headers.Add("prompt", "login");


var httpresponse = httpWebRequest.GetResponse();