Why does an error occur during HTTPS authentication?

Question

C++ / C#

Hello!
I have a custom C# HTTPS server and when I connect to it I get the following error:

System.ComponentModel.Win32Exception: "Credential missing from security package"

This is the server startup code:

certificate = X509Certificate2.CreateFromPemFile("www/certificate/fullchain.pem", "www/certificate/privkey.pem");
 
server = new TcpListener(IPAddress.Parse("192.168.1.200"), 40000);
server.Start();
while (true)
{
     new Thread(new ParameterizedThreadStart(ServeClient)).Start(server.AcceptTcpClient());
}

And this is the code for customer service:

SslStream stream = new SslStream(client.GetStream(), false);
stream.AuthenticateAsServer(certificate, false, true); // тут получаю ошибку
 
string HTTPREQUEST = ReadMessage(stream, client);
 
var match = Regex.Match(HTTPREQUEST, "^([^ ]+) ([^ ]+)");
 
string METHOD = match.Groups[1].Value;
string PATH = match.Groups[2].Value;
 
Console.WriteLine("METHOD=" + METHOD + "; PATH=" + PATH + "\n" + HTTPREQUEST + "\n");

SSL certificate is correct, I checked. Tried to run as administrator. Nothing works.
Help me please!
Thanks in advance.

Answer 1

The problem turned out to be in C# itself.
Should have been replaced

certificate = X509Certificate2.CreateFromPemFile("www/certificate/fullchain.pem", "www/certificate/privkey.pem");

on the

certificate = new X509Certificate2(X509Certificate2.CreateFromPemFile("www/certificate/fullchain.pem", "www/certificate/privkey.pem").Export("X509ContentType.Pkcs12"));

Answer 2

Check https://www.ssllabs.com/ssltest/index.html or another validator.
One possibility is that you (on the client's machine) do not have the appropriate CA cert.