API response = 400 Bad Request / HttpWebResponse response = NULL

Hi guys, we've been using the script below and it has been working for a month but it suddenly stopped working yesterday.

2 things to note:

1. bulk import was done prior to yesterday (created +100K companies) via the Freshdesk site.

2. API request is still working via Postman using the same credentials.

Error encountered:

1. using breakpoints we saw value of response = NULL

2. [ctrl+F5] shows 400 Bad Request error:

Any ideas would be appreciated. TIA!

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Threading.Tasks;
using System.Net;
using System.IO;

namespace ConsoleApp2
{
    class Program
    {
        static void Main(string[] args)
        {
            string fdDomain = "[domain]"; // your freshdesk domain
            string apiKey = "[API key]";
            string apiPath = "/api/v2/tickets/"; // API path

            string responseBody = String.Empty;
            HttpWebRequest request = (HttpWebRequest)WebRequest.Create("https://" + fdDomain + ".freshdesk.com" + apiPath);
            
            request.ContentType = "application/json";
            request.Method = "GET";
            string authInfo = apiKey + ":X"; // It could be your username:password also.
            authInfo = Convert.ToBase64String(Encoding.Default.GetBytes(authInfo));
            request.Headers["Authorization"] = "Basic " + authInfo;
                        
            try
            {
                Console.WriteLine("Submitting Request");
                using (HttpWebResponse response = (HttpWebResponse)request.GetResponse())
                {
                    Stream dataStream = response.GetResponseStream();
                    StreamReader reader = new StreamReader(dataStream);
                    responseBody = reader.ReadToEnd();
                    reader.Close();
                    dataStream.Close();
                    //return status code
                    Console.WriteLine("Status Code: {1} {0}", ((HttpWebResponse)response).StatusCode, (int)((HttpWebResponse)response).StatusCode);
                }
                Console.Out.WriteLine(responseBody);
            }
            catch (WebException ex)
            {
                Console.WriteLine("API Error: Your request is not successful. If you are not able to debug this error properly, mail us at support@freshdesk.com with the follwing X-Request-Id");
                Console.WriteLine("X-Request-Id: {0}", ex.Response.Headers["X-Request-Id"]);
                Console.WriteLine("Error Status Code : {1} {0}", ((HttpWebResponse)ex.Response).StatusCode, (int)((HttpWebResponse)ex.Response).StatusCode);
                using (var stream = ex.Response.GetResponseStream())
                using (var reader = new StreamReader(stream))
                {
                    Console.Write("Error Response: ");
                    Console.WriteLine(reader.ReadToEnd());
                }
            }
            catch (Exception ex)
            {
                Console.WriteLine("ERROR");
                Console.WriteLine(ex.Message);
            }
        }
    }
}