Bot Channels Registration SocketException - An existing connection was forcibly closed by the remote host

Question

I have an Azure Web App with ASP.NET REST API application to behave as service for Bot Channels Registration.

In this app, I have one endpoint

 public async Task<IHttpActionResult> Post(string userToken, string botName, [FromBody] Activity activity)

where I receive a message from the user, process it and send back.

When I trying to communicate back to the user (either with typing activity or with an actual answer)

private static async Task ShowTyping(Activity activity, ConnectorClient client)
{
    var typingResponse = new Activity
    {
        Conversation = activity.Conversation,
        From = activity.Recipient,
        Locale = activity.Locale,
        Recipient = activity.From,
        ReplyToId = activity.Id,
        Id = activity.Id,
        Type = "typing"
    };
    await client.Conversations.UpdateActivityAsync(typingResponse);
}

...

foreach (var reply in replies)
{
      Trace.TraceInformation($"[{userToken}:{botName}] Sending reply {reply.Id}:{reply.Text}");
      await client.Conversations.ReplyToActivityAsync(reply);
}

through REST API I receive HttpRequestException - An existing connection was forcibly closed by the remote host:

2019-01-22T15:49:54  PID[17864] Error       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 Microsoft.Rest.RetryDelegatingHandler.<SendAsync>d__15.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 System.Runtime.CompilerServices.TaskAwaiter.ValidateEnd(Task task)    at Microsoft.Bot.Connector.Conversations.<UpdateActivityWithHttpMessagesAsync>d__9.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 Microsoft.Bot.Connector.ConversationsExtensions.<UpdateActivityAsync>d__16.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 ChatFirst.Channels.BotFramework.Controllers.WebhookController.<ShowTyping>d__5.MoveNext()

Everything works fine on emulator and doesn't work at all in the web service. I tried to implement REST API client by myself but got the same result.

What am I missing?

More information on the issue

I use v4.2 Bot Framework packages

<package id="Microsoft.Bot.Builder" version="4.2.0" targetFramework="net472" /> <package id="Microsoft.Bot.Connector" version="4.2.0" targetFramework="net472" /> <package id="Microsoft.Bot.Schema" version="4.2.0" targetFramework="net472" />

Entire Post method, userToken and botName are my internal credentials

/// <summary>
///     POST: api/v1/webhook/{userToken}/{botName}
///     Receive a message from a user and reply to it
/// </summary>
[HttpPost]
[Route("api/v1/webhook/{userToken}/{botName}")]
public async Task<IHttpActionResult> Post(string userToken, string botName, [FromBody] Activity activity)
{
    try
    {
        if (activity.Type == ActivityTypes.Message)
        {
            Trace.TraceInformation($"[{userToken}:{botName}] Message from {activity.From.Id}");
            MicrosoftAppCredentials credentials = _channelGateway.GetCredentials(userToken, botName);

            if (credentials == null)
                return Ok();

            var serviceUri = new Uri(activity.ServiceUrl);
            var client = new ConnectorClient(serviceUri, credentials);

            await ShowTyping(activity, client);

            IEnumerable<Activity> replies = await _coreTalkService.GetRepliesAsync(new BotToken(userToken, botName), activity);

            foreach (var reply in replies)
            {
                Trace.TraceInformation($"[{userToken}:{botName}] Sending reply {reply.Id}:{reply.Text}");
                await client.Conversations.ReplyToActivityAsync(reply);
            }
        }
        else
        {
            HandleSystemMessage(activity);
        }

        return Ok();
    }
    catch (Exception e)
    {
        Trace.TraceError(e.ToString());
        return InternalServerError(e);
    }
}

Bot Channels Registrations settings looks like this
If I reroute Bot Channel to the local instance on my dev PC through ngrok I receive the same errors.
I reduced entire method to perform simple echo answer, but error still remains

public async Task<IHttpActionResult> Post(string userToken, string botName, [FromBody] Activity activity)
{
    Trace.TraceInformation($"[{userToken}:{botName}] Message from {activity.From.Id}");
    var client = new ConnectorClient(new Uri(activity.ServiceUrl), 
        new MicrosoftAppCredentials("<secret>", "<secret>"));
    var answer = activity.CreateReply(activity.Text, activity.Locale);
    await client.Conversations.ReplyToActivityAsync(answer);
    return Ok();
}

activity.ServiceUrl is https://webchat.botframework.com/
Error happens if message sent through webchat, i didn't check another channels

Hmm, well that's a pretty low level network disconnect exception you're reporting there. How are you configuring the client? Have you set up your credentials? Does this happen to the very first message being sent via the client or...? — Drew Marsh
Your Post method does not look like a normal Messaging Endpoint. Are you bypassing the connector services and calling the bot directly? Please share the client side code you are using to communicate with the bot. — Eric Dahlvang
Thank you for your time. I hope I provided enough information to clarify the problem. It should be a simple task, but I have no idea why it's not working. — xakpc
You've changed the messaging endpoint signature. The webchat control is going to call the Direct Line connector service, which will in turn call your bot's Messaging Endpoint (not sending any userToken or botName). — Eric Dahlvang
@EricDahlvang usetToken and botName are my internal credentials, as far as I understand for Messaging Endpoint there is no difference between https://link/api/v1/webhook or https://link/api/v1/webhook/a/b. Furthermore, I do receive user messages normally, the exception occurs when I try to reply it. — xakpc

Eric Dahlvang Eric Dahlvang · Accepted Answer · 2019-02-01T18:40:02

The only thing I can think of is there must be some referenced library that is interfering with the outgoing messages in your project.

Rather than attempt to debug your project, I created a new similar project that works as expected: https://github.com/xakpc/BotFrameworkChannel.Test/pull/1

Bot Channels Registration SocketException - An existing connection was forcibly closed by the remote host

2 Answers