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

I’m seeing this error when I try and log to Seq. Any suggestions?

It’s a .NET 4.8 ASP.NET MVC App

Sample code I’m using AutoFac IoC to inject a logger and then triggering it from there:

public class SerilogLogger
    {
        public SerilogLogger()
        {
            Log.Logger = new LoggerConfiguration()
                       .ReadFrom.AppSettings()
                       .CreateLogger();

            Serilog.Debugging.SelfLog.Enable(
                msg => System.Diagnostics.Trace.WriteLine(msg));
        }

        public void Info(object message)
        {
            Log.Logger.Information(message.ToString());
            Log.CloseAndFlush();
        }

// in IoC class
builder.RegisterType<SerilogLogger>().As<ILogger>();

// Test to trigger log message
public class TestClass 
{
    private ILogger logger;
    public TestClass(ILogger logger)
    {
        this.logger = logger;
    }

    public void TestMethod()
    {
        logger.Info("Testing from website");
    }
}

Full stack trace from SelfLog:

2020-06-16T09:35:51.2143660Z Exception while emitting periodic batch from Serilog.Sinks.Seq.SeqSink: System.Net.Http.HttpRequestException: An error occurred while sending the request. ---> System.Net.WebException: The underlying connection was closed: An unexpected error occurred on a send. ---> System.IO.IOException: Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host. ---> System.Net.Sockets.SocketException: An existing connection was forcibly closed by the remote host
   at System.Net.Sockets.Socket.EndReceive(IAsyncResult asyncResult)
   at System.Net.Sockets.NetworkStream.EndRead(IAsyncResult asyncResult)
   --- End of inner exception stack trace ---
   at System.Net.TlsStream.EndWrite(IAsyncResult asyncResult)
   at System.Net.PooledStream.EndWrite(IAsyncResult asyncResult)
   at System.Net.ConnectStream.WriteHeadersCallback(IAsyncResult ar)
   --- End of inner exception stack trace ---
   at System.Net.HttpWebRequest.EndGetRequestStream(IAsyncResult asyncResult, TransportContext& context)
   at System.Net.Http.HttpClientHandler.GetRequestStreamCallback(IAsyncResult ar)
   --- End of inner exception stack trace ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Serilog.Sinks.Seq.SeqSink.<EmitBatchAsync>d__14.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Serilog.Sinks.PeriodicBatching.PeriodicBatchingSink.<OnTick>d__16.MoveNext()
2020-06-16T09:35:51.3180195Z Exception while emitting periodic batch from Serilog.Sinks.Seq.SeqSink: System.Net.Http.HttpRequestException: An error occurred while sending the request. ---> System.Net.WebException: The underlying connection was closed: An unexpected error occurred on a send. ---> System.IO.IOException: Unable to read data from the transport connection: An existing connection was forcibly closed by the remote host. ---> System.Net.Sockets.SocketException: An existing connection was forcibly closed by the remote host
   at System.Net.Sockets.Socket.EndReceive(IAsyncResult asyncResult)
   at System.Net.Sockets.NetworkStream.EndRead(IAsyncResult asyncResult)
   --- End of inner exception stack trace ---
   at System.Net.TlsStream.EndWrite(IAsyncResult asyncResult)
   at System.Net.PooledStream.EndWrite(IAsyncResult asyncResult)
   at System.Net.ConnectStream.WriteHeadersCallback(IAsyncResult ar)
   --- End of inner exception stack trace ---
   at System.Net.HttpWebRequest.EndGetRequestStream(IAsyncResult asyncResult, TransportContext& context)
   at System.Net.Http.HttpClientHandler.GetRequestStreamCallback(IAsyncResult ar)
   --- End of inner exception stack trace ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Serilog.Sinks.Seq.SeqSink.<EmitBatchAsync>d__14.MoveNext()
--- End of stack trace from previous location where exception was thrown ---
   at System.Runtime.CompilerServices.TaskAwaiter.ThrowForNonSuccess(Task task)
   at System.Runtime.CompilerServices.TaskAwaiter.HandleNonSuccessAndDebuggerNotification(Task task)
   at Serilog.Sinks.PeriodicBatching.PeriodicBatchingSink.<OnTick>d__16.MoveNext()

Thanks!

[grjw]

Hi @nblumhardt

Thanks for the suggestions, I really appreciate it. I have found now found the issue.

Googling the error, a few people mention not using TLS1.2 can trigger this. Someone else also said Seq needs TLS1.2. Looking at Wireshark, my prototype (which works) is using TLS1.2 and the website (which doesn’t) is using TLS1. Both are .NET 4.8

I had upgraded my MVC project to 4.8 for that reason but completely forgot about the httpruntime targetFramework attribute in web.config, It was still set to 4.5. Changing that to 4.8 has fixed it.

Thanks also for the suggestions about using SingleInstance - I’ll update that as well.

[nblumhardt]

Ah, sorry - also, Autofac will be disposing that InstancePerDependency() logger per request, which will also potentially cause trouble. Definitely SingleInstance() 😃