How to get response JSON of an API which returns Http Status Code 406 or 400

Question

Postman returns some response JSON with HTTP status code 406 but my code which is written in C# returns the same HTTP status code error message but from Catch Block.

My Requirement is

The API I am consuming always returns some response JSON either the HTTP status code 200 or 400 or any other. When I test these API from post man it show response JSON but my code returns error when I execute the following line.

HttpWebResponse response = (HttpWebResponse)request.GetResponse();

Here is my complete method.

private Dictionary<string, string> HTTPCall(CRMRequestData requestData, out bool isError, out string errorMessage)
        {
            isError = true;
            errorMessage = "HTTPCall - initial error!";
            try
            {
                ServicePointManager.SecurityProtocol = TLS12;

                Dictionary<string, string> responseBag = new Dictionary<string, string>();
                HttpWebRequest request = (HttpWebRequest)WebRequest.Create(requestData.Uri);
                
                request.Method = requestData.HttpMethodName;
                request.ContentType = requestData.ContentType;
                request.ContentLength = string.Format("{0}", requestData.Body).Length;
                request.Headers.Add("x-api-key", requestData.APIKey);
                if (requestData.Authorization != null)
                {
                    request.Headers.Add("Authorization", string.Format("JWT {0}",requestData.Authorization));
                }

                if (requestData.HttpMethodName.ToUpper().Equals("POST"))
                {
                    string body = requestData.Body;
                    Byte[] bytes = Encoding.UTF8.GetBytes(body);
                    using (Stream stream = request.GetRequestStream())
                    {
                        stream.Write(bytes, 0, bytes.Length);
                    }
                }

                HttpWebResponse response = (HttpWebResponse)request.GetResponse();//#Error at this line

                
                string responseData = new StreamReader(response.GetResponseStream()).ReadToEnd();

                if (responseData != null && responseData != "")
                {
                    responseBag = ReadResponseJSON(responseData, requestData.CRMMethod, out isError, out errorMessage);
                }

                errorMessage = (!isError) ? "HTTPCall - API executed successfully!" : errorMessage;
                return responseBag;
            }
            catch (Exception ex)
            {
                isError = true;
                errorMessage = string.Format("{0}", ex.Message);
            }
            return null;
        }

* Note: - My code block works fine when API returns the HTTP status code 200 or 201

Answer 1

Try this: What is "406-Not Acceptable Response" in HTTP?

In short: Add Accept header for the response (content type) returned by Service