Authentication failed because the remote party sent a TLS alert: 'HandshakeFailure'

Question

I have a .NET Console 6 to access API data. The application works on my desktop (Windows 10) but an error "System.Net.Http.HttpRequestException: The SSL connection could not be established" is thrown when running the application on Windows Server 2012 R2. The code is below.

private static async Task<string> GetBobjDataAsync(string path)
{
var handler = new HttpClientHandler
{
UseDefaultCredentials = true
};
var bobj = new HttpClient(handler);

        HttpResponseMessage response = await bobj.GetAsync(new Uri(path));
        if (response.IsSuccessStatusCode)
        {
            return response.Content.ReadAsStringAsync().Result;
        }
        else
        {
            return response.StatusCode.ToString();
        }
    }

My Windows Server 2012 R2 is using TLS 1.2. How can I resolve this TLS issue?

Thanks in advance!!

Answer 1

I have a same issue , After some windows 10 Enterprise 20H2 updates all my httpClient request are failing with

Authentication failed because the remote party sent a TLS alert: '112'.

Here is the sample i am trying on .net 6 Azure Function, Any help is appreciated.

 var httpClientHandler = new HttpClientHandler                
{
                    SslProtocols = System.Security.Authentication.SslProtocols.Tls12 | System.Security.Authentication.SslProtocols.Tls13 | System.Security.Authentication.SslProtocols.Tls11,
                    UseDefaultCredentials = true
                };

                using var client = new HttpClient(httpClientHandler);                
                client.Timeout = TimeSpan.FromSeconds(3000);
                var msg = new HttpRequestMessage(HttpMethod.Get, uri);   
                var res = await client.SendAsync(msg);

Answer 2

Thank you all!

The issue got resolved after the (SAP) site updated their software.