Query token using HTTPS

I try to connect to the following address to obtain a token, I try it in the following ways, but in all of them I get a query error, these are the examples I use for the query and the routes as they are created:

string client_id = "api-stag";// CLIENT ID = api-stag
            string client_secret = "";// CLIENT SECRET = [VACIO]
            string scope = "";// SCOPE = [VACIO]
            string url = "https://idp.comprobanteselectronicos.go.cr/auth/realms/rut-stag/protocol/openid-connect/token/" + "?CLIENT ID={" + client_id + "}&CLIENT SECRET={" + client_secret + "}&SCOPE={" + scope + "}";
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create(url);
            HttpWebResponse response = (HttpWebResponse)request.GetResponse();
            Stream resStream = response.GetResponseStream();

try with the following code in the same way:

string client_id = "api-stag";// CLIENT ID = api-stag
            string client_secret = "";// CLIENT SECRET = [VACIO]
            string scope = "";// SCOPE = [VACIO]

            byte[] data = Encoding.ASCII.GetBytes($"CLIENT ID={client_id}&CLIENT SECRET={client_secret}&SCOPE={scope}");

            WebRequest request = WebRequest.Create("https://idp.comprobanteselectronicos.go.cr/auth/realms/rut-stag/protocol/openid-connect/token");
            request.Method = "POST";
            request.ContentType = "application/x-www-form-urlencoded";
            request.ContentLength = data.Length;
            using (Stream stream = request.GetRequestStream())
            {
                stream.Write(data, 0, data.Length);
            }

            string responseContent = null;

            using (WebResponse response = request.GetResponse())
            {
                using (Stream stream = response.GetResponseStream())
                {
                    using (StreamReader sr99 = new StreamReader(stream))
                    {
                        responseContent = sr99.ReadToEnd();
                    }
                }
            }

            MessageBox.Show(responseContent);

I created the following links, but none works, in these ways or other proven

"https://idp.comprobanteselectronicos.go.cr/auth/realms/rut-stag/protocol/openid-connect/token/?CLIENT ID={api-stag}&CLIENT SECRET={}&SCOPE={}"
"https://idp.comprobanteselectronicos.go.cr/auth/realms/rut-stag/protocol/openid-connect/token/?CLIENT_ID={api-stag}&CLIENT_SECRET={}&SCOPE={}"
"https://idp.comprobanteselectronicos.go.cr/auth/realms/rut-stag/protocol/openid-connect/token/?CLIENT_ID=api-stag&CLIENT_SECRET=&SCOPE="
"https://idp.comprobanteselectronicos.go.cr/auth/realms/rut-stag/protocol/openid-connect/token/?CLIENT_ID='api-stag'&CLIENT_SECRET=''&SCOPE=''"