runtime: Received an unexpected EOF or 0 bytes from the transport stream

I am trying to use a WPF application that use gRPC to connect to a service that is hosted in an ASP Core application.

The ASP Core has this code:

using GestorOrdenadores.Service.Server.Host.AspCore.Services;
using Microsoft.AspNetCore.Server.Kestrel.Core;
using System.Security.Cryptography.X509Certificates;

var builder = WebApplication.CreateBuilder(args);


builder.WebHost.ConfigureKestrel((context, options) =>
{
    string miStrCertificado = File.ReadAllText("certificados/client.crt");
    string miStrKey = File.ReadAllText("certificados/client.key");
    X509Certificate2 miCertficadoX509 = X509Certificate2.CreateFromPem(miStrCertificado, miStrKey);

    options.ListenAnyIP(5001, listenOptions =>
    {
        listenOptions.Protocols = HttpProtocols.Http1AndHttp2;
        listenOptions.UseHttps(miCertficadoX509);
    });
});




builder.Services.AddGrpc();


var app = builder.Build();

app.MapGrpcService<GreeterService>();

app.MapGet("/", () => "Communication with gRPC endpoints must be made through a gRPC client. To learn how to create a client, visit: https://go.microsoft.com/fwlink/?linkid=2086909");

app.Run();

This is the code in the code in my WPF application:

HttpClientHandler miHttpHandler = new HttpClientHandler();
            miHttpHandler.SslProtocols = System.Security.Authentication.SslProtocols.Tls12;
            miHttpHandler.ClientCertificates.Add(cert);
            HttpClient httpClient = new(miHttpHandler);


            var channel = GrpcChannel.ForAddress("https://localhost:5001", new GrpcChannelOptions
            {
                HttpClient = httpClient
            });


            var miCliente = new Greeter.GreeterClient(channel);

            HelloRequest miRequest = new HelloRequest()
            {
                Name = "MiNombre"
            };

            return (await miCliente.SayHelloAsync(miRequest)).Message;

By the moment, I am running the service and the client in the same machine.

But I get the error: Received an unexpected EOF or 0 bytes from the transport stream.

This is the complete error message:

{"Status(StatusCode=\"Unavailable\", Detail=\"Error starting gRPC call. HttpRequestException: The SSL connection could not be established, see inner exception. IOException:  Received an unexpected EOF or 0 bytes from the transport stream.\", DebugException=\"System.Net.Http.HttpRequestException: The SSL connection could not be established, see inner exception.\r\n
 ---> System.IO.IOException:  Received an unexpected EOF or 0 bytes from the transport stream.\r\n
   at System.Net.Security.SslStream.<FillHandshakeBufferAsync>g__InternalFillHandshakeBufferAsync|189_0[TIOAdapter](TIOAdapter adap, ValueTask`1 task, Int32 minSize)\r\n
   at System.Net.Security.SslStream.ReceiveBlobAsync[TIOAdapter](TIOAdapter adapter)\r\n
   at System.Net.Security.SslStream.ForceAuthenticationAsync[TIOAdapter](TIOAdapter adapter, Boolean receiveFirst, Byte[] reAuthenticationData, Boolean isApm)\r\n
   at System.Net.Http.ConnectHelper.EstablishSslConnectionAsync(SslClientAuthenticationOptions sslOptions, HttpRequestMessage request, Boolean async, Stream stream, CancellationToken cancellationToken)\r\n
   --- End of inner exception stack trace ---\r\n
   at System.Net.Http.ConnectHelper.EstablishSslConnectionAsync(SslClientAuthenticationOptions sslOptions, HttpRequestMessage request, Boolean async, Stream stream, CancellationToken cancellationToken)\r\n
   at System.Net.Http.HttpConnectionPool.ConnectAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)\r\n
   at System.Net.Http.HttpConnectionPool.AddHttp2ConnectionAsync(HttpRequestMessage request)\r\n
   at System.Threading.Tasks.TaskCompletionSourceWithCancellation`1.WaitWithCancellationAsync(CancellationToken cancellationToken)\r\n
   at System.Net.Http.HttpConnectionPool.GetHttp2ConnectionAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)\r\n
   at System.Net.Http.HttpConnectionPool.SendWithVersionDetectionAndRetryAsync(HttpRequestMessage request, Boolean async, Boolean doRequestAuth, CancellationToken cancellationToken)\r\n
   at System.Net.Http.RedirectHandler.SendAsync(HttpRequestMessage request, Boolean async, CancellationToken cancellationToken)\r\n
   at System.Net.Http.HttpClient.<SendAsync>g__Core|83_0(HttpRequestMessage request, HttpCompletionOption completionOption, CancellationTokenSource cts, Boolean disposeCts, CancellationTokenSource pendingRequestsCts, CancellationToken originalCancellationToken)\r\n
   at Grpc.Net.Client.Internal.GrpcCall`2.RunCall(HttpRequestMessage request, Nullable`1 timeout)\")"}

This is the script that I use to create the certficates with OpenSsl:

set path=.\OpenSsl
set OPENSSL_CONF=.\openssl.cfg


# Generate valid CA
openssl genrsa -passout pass:1234 -des3 -out ca.key 4096
openssl req -passin pass:1234 -new -x509 -days 365 -key ca.key -out ca.crt -subj  "/C=SP/ST=Spain/L=Valdepenias/O=Test/OU=Test/CN=Root CA"

# Generate valid Server Key/Cert
openssl genrsa -passout pass:1234 -des3 -out server.key 4096
openssl req -passin pass:1234 -new -key server.key -out server.csr -subj "/CN=localhost" -config openssl.cfg
openssl x509 -req -passin pass:1234 -days 365 -in server.csr -CA ca.crt -CAkey ca.key -set_serial 01 -out server.crt

# Remove passphrase from the Server Key
openssl rsa -passin pass:1234 -in server.key -out server.key

# Generate valid Client Key/Cert
openssl genrsa -passout pass:1234 -des3 -out client.key 4096
openssl req -passin pass:1234 -new -key client.key -out client.csr -subj  "/C=SP/ST=Spain/L=Valdepenias/O=Test/OU=Client/CN=Client"
openssl x509 -passin pass:1234 -req -days 365 -in client.csr -CA ca.crt -CAkey ca.key -set_serial 01 -out client.crt

# Remove passphrase from Client Key
openssl rsa -passin pass:1234 -in client.key -out client.key




pause

Really I don’t know if the problem is that I didn’t create the certificates correctly, perhaps because of a wrong CN or another data, or perhaps because I don’t configure correctly the service or the client.

Thanks.