403 Error code for cs sample

[Onotseike]

Hello I am trying to implement the REST STT in asp.net core app and I get a 403 forbidden code:
Here is my relevant code:
`STTModel sttModel = new STTModel();
string host = @"westus.api.cognitive.microsoft.com";
string contentType = @"audio/wav; codec=""audio/pcm""; samplerate=16000";
string requestUri = "https://speech.platform.bing.com/speech/recognition/conversation/cognitiveservices/v1?language=en-US&format=detailed";// args[0];
// string requestUri = "https://westus.stt.speech.microsoft.com/speech/recognition/conversation/cognitiveservices/v1?language=en-US&format=detailed";
///*
// * Input your own audio file or use read from a microphone stream directly.
// */
string audioFile = destFile; //args[1];
string responseString;
FileStream fs = null;

        try

        {

            var token = sttModel.GetAccessToken();

            Console.WriteLine("Token: {0}\n", token);

            Console.WriteLine("Request Uri: " + requestUri + Environment.NewLine);


            var request = (HttpWebRequest)WebRequest.Create(requestUri);

            request.SendChunked = true;

            request.Accept = @"application/json;text/xml";

            request.Method = "POST";

            request.ProtocolVersion = HttpVersion.Version11;

            request.Host = host;

            request.ContentType = contentType;

            request.Headers["Authorization"] = "Bearer " + token;
            //request.Expect = "100-continue";
            //request.Headers["Ocp-Apim-Subscription-Key"] = "09ae100b29fe4defb6fe7f0519040889";




            using (fs = new FileStream(audioFile, FileMode.Open, FileAccess.Read))

            {



                /*

                 * Open a request stream and write 1024 byte chunks in the stream one at a time.

                 */

                byte[] buffer = null;

                int bytesRead = 0;

                using (Stream requestStream = request.GetRequestStream())

                {

                    /*

                     * Read 1024 raw bytes from the input audio file.

                     */

                    buffer = new Byte[checked((uint)Math.Min(1024, (int)fs.Length))];

                    while ((bytesRead = fs.Read(buffer, 0, buffer.Length)) != 0)

                    {

                        requestStream.Write(buffer, 0, bytesRead);

                    }



                    // Flush

                    requestStream.Flush();

                }



                /*

                 * Get the response from the service.

                 */
                ServicePointManager
                        .ServerCertificateValidationCallback +=
                    (sender, cert, chain, sslPolicyErrors) => true;
                Console.WriteLine("Response:");

                using (WebResponse response = request.GetResponse())

                {
                    Console.WriteLine("Responnse:");
                    Console.WriteLine(((HttpWebResponse)response).StatusCode);

                    Console.WriteLine("Responnnnse:");

                    using (StreamReader sr = new StreamReader(response.GetResponseStream() ?? throw new InvalidOperationException()))

                    {

                        responseString = sr.ReadToEnd();

                    }



                    Console.WriteLine(responseString);

                    Console.ReadLine();

                }

            }

        }

        catch (Exception ex)

        {

            Console.WriteLine(ex.ToString());

            Console.WriteLine(ex.Message);

            Console.ReadLine();

        }

`