.NET 5 HttpClient: SSL connection could not be established, see inner exception

I am using HttpClient to get an image from a public url. I did a test in Postman and I can get it without any issues, as well as in my dev pc. When I publish it to production web server, I got the error: "The SSL connection could not be established, see inner exception.", right after GetByteArrayAsync().
Inner Exception:

System.Security.Authentication.AuthenticationException: Authentication failed because the remote party sent a TLS alert: 'ProtocolVersion'. ---> System.ComponentModel.Win32Exception (0x80090326): The message received was unexpected or badly formatted. --- End of inner exception stack trace --- at System.Net.Security.SslStream.ForceAuthenticationAsync[TIOAdapter](TIOAdapter adapter, Boolean receiveFirst, Byte[] reAuthenticationData, Boolean isApm) at System.Net.Http.ConnectHelper.EstablishSslConnectionAsyncCore(Boolean async, Stream stream, SslClientAuthenticationOptions sslOptions, CancellationToken cancellationToken)

This is the code that is working in my dev pc:

var client = new HttpClient();
ServicePointManager.SecurityProtocol = SecurityProtocolType.Tls12 | SecurityProtocolType.Tls11 | SecurityProtocolType.Tls;
            ServicePointManager.ServerCertificateValidationCallback += (sender, certificate, chain, sslPolicyErrors) => true;
var result = await client.GetByteArrayAsync("url");

Since this code is not working in production, I have added (and still not working):

client.DefaultRequestHeaders.Add("Accept-Encoding", "gzip");
 client.DefaultRequestHeaders.Add("Accept-Encoding", "deflate");
 client.DefaultRequestHeaders.Add("Accept-Encoding", "br");

And also using HttpRequestMessage and HttpClientHandler, I got the same issue in production:

var handler = new HttpClientHandler();
handler.ServerCertificateCustomValidationCallback = HttpClientHandler.DangerousAcceptAnyServerCertificateValidator;
using (var client = new HttpClient(handler))
using (var request = new HttpRequestMessage(HttpMethod.Get, "url"))
{
request.Headers.Host = "url";
using (var response = await client.SendAsync(request))
 {
    Console.WriteLine(response.StatusCode);
 }

So, do you know what the issue in production would be? why this works in dev and Postman but not in production? do I need to set up a setting?
Also, when I change the target to another public url, I can get an image from production server without issues.
Any help will be appreciated. Thanks

Thanks to @Charlieface for the SSLLab report I found out that the target server was working with TLS 1.3 only, and my web hosting provider was working with Windows 2019 where that protocole is not available. So, I changed the hosting provider with Window 2022 and my web app is working fine.
Thanks.