I set up a proxy through Windows settings (Internet Options) (proxy type is pac)

All Browsers work well with proxies (so proxy is active and working), but when I try to use httpclient, I get the following error

SocketException: An existing connection was forcibly closed by the remote host.

this is my codes

using (HttpClient client = new HttpClient())
            {
                
                using (HttpResponseMessage response = await client.GetAsync(url))
                {
                    using (HttpContent content = response.Content)
                    {
                        return await content.ReadAsStringAsync();
                    }
                }
            }

How can I use a proxy set on Windows in my app?