I have written this HTTPS Client code to get data from NSE Server.
On button click, the code is expected to send a request to the Server and get data in return.
Half the times when I click the button I don’t get data from the Server, and it returns me Status Code 401 – Unauthorized. But other half of the times when I click the button, the server returns me the required data and a Status Code 200.

I am sending a GET Request to the Server

This is my Code,

    private void Button_Click(object sender, RoutedEventArgs e)
    {
        ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls13;

        string baseUrl = "https://www.nseindia.com/api/reports?archives=";
        string encodedurl = "[{"name":"Full Bhavcopy and Security Deliverable data","type":"daily-reports","category":"capital-market","section":"equities"}]";
        string endurl = "&date=31-Jul-2024&type=equities&mode=single"; 
        string url = baseUrl + Uri.EscapeDataString(encodedurl)+endurl;

        GetRequest(url);

    }

    async static void GetRequest(string url)
    {

        using (HttpClient client = new HttpClient())
        {
            
            client.DefaultRequestHeaders.Add("Accept", "*/*");
            client.DefaultRequestHeaders.Add("Referer", "https://www.nseindia.com/all-reports");
            client.DefaultRequestHeaders.Add("sec-ch-ua", ""Not)A;Brand";v="99", "Brave";v="127", "Chromium";v="127"");
           
              client.DefaultRequestHeaders.Add("user-agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/127.0.0.0 Safari/537.36");
            client.DefaultRequestHeaders.Add("x-requested-with", "XMLHttpRequest");

            client.DefaultRequestHeaders.Add("Dnt", "1");




            using (HttpResponseMessage response = await client.GetAsync(url))
            {

                using(HttpContent content = response.Content)
                {

                    string myContent = await content.ReadAsStringAsync();

                }
            }

        }
    }

The exact same code is running successfully sometimes but sometimes returning me error. I have spent an entire day but still unable to find the reason for this weird code behavior.

Please guide me.