I have an issues while I want to get Order statistic /fapi/v1/openOrders

My URL the following:
https://fapi.binance.com/fapi/v1/openOrders?timestamp=1712840260000&signature=c4945231644bd4f31fa0747ccf85b5c488d3697e402883814dcf1a4e0c3c2c0c
Everytime I got this :
{StatusCode: 400, ReasonPhrase: ‘Bad Request’, Version: 1.1, Content: System.Net.Http.StreamContent, Headers:
{
Connection: keep-alive
x-mbx-used-weight-1m: 61
x-response-time: 0ms
Access-Control-Allow-Origin: *
Access-Control-Allow-Methods: GET, POST, PUT, DELETE, OPTIONS
Date: Thu, 11 Apr 2024 12:57:32 GMT
Server: Tengine
Content-Length: 88
Content-Type: application/json
}}
What I do wrong?

My method:

public async void OrderStatus(string symbol = "btcusdt")
        {
           //string depthEndpoint = $"https://fapi.binance.com/fapi/v1/openOrders";

            string endpoint = "/fapi/v1/openOrders";
            string timestamp = DateTimeOffset.UtcNow.ToUnixTimeMilliseconds().ToString();
            string queryString = $"timestamp={timestamp}"; 
            string signature = GenerateSignature(queryString, BinanceOptionsApp.Models.Credential.Sec);
            string requestUrl = $"https://fapi.binance.com{endpoint}?{queryString}&signature={signature}";
            
            var path = new Uri(requestUrl);

            HttpResponseMessage response = await _httpClient.GetAsync(path);

            if (response.IsSuccessStatusCode)
            {
                response.EnsureSuccessStatusCode();
                var result = await response.Content.ReadAsStringAsync().ConfigureAwait(false);

            }
        }