"The CancellationTokenSource has been disposed" error in Teams when using Microsoft.Bot.Components.Recognizers.CustomQuestionAnsweringRecognizer

I am using Microsoft.Bot.Components.Recognizers.CustomQuestionAnsweringRecognizer for enabling my CQA resource in my Bot built-in Bot Composer. When I publish a new version of the bot to Azure Bot Service, my bot stops answering and I get the error “The CancellationTokenSource has been disposed”. I have debugged and found out that it is indeed when CQA dialog that is causing this problem. Here is the entire error code:

Exception: System.ObjectDisposedException: The CancellationTokenSource has been disposed.    at System.Threading.CancellationTokenSource.ThrowObjectDisposedException()    at System.Threading.CancellationTokenSource.Cancel()    at Microsoft.Bot.Builder.ShowTypingMiddleware.FinishTypingTaskAsync(ITurnContext turnContext)    at Microsoft.Bot.Builder.ShowTypingMiddleware.<OnTurnAsync>b__4_0(ITurnContext ctx, List1 activities, Func1 nextSend)    at Microsoft.Bot.Builder.TelemetryLoggerMiddleware.<>c__DisplayClass7_0.<<OnTurnAsync>b__0>d.MoveNext() — End of stack trace from previous location where exception was thrown —    at Microsoft.Bot.Builder.TurnContext.SendActivityAsync(IActivity activity, CancellationToken cancellationToken)    at Microsoft.Bot.Builder.TurnContext.SendActivityAsync(String textReplyToSend, String speak, String inputHint, CancellationToken cancellationToken)    at Microsoft.Bot.Builder.Dialogs.Adaptive.Runtime.CoreBotAdapter.<.ctor>b__0_0(ITurnContext turnContext, Exception exception)    at Microsoft.Bot.Builder.BotAdapter.RunPipelineAsync(ITurnContext turnContext, BotCallbackHandler callback, CancellationToken cancellationToken)    at Microsoft.Bot.Builder.CloudAdapterBase.ProcessActivityAsync(AuthenticateRequestResult authenticateRequestResult, Activity activity, BotCallbackHandler callback, CancellationToken cancellationToken)    at Microsoft.Bot.Builder.CloudAdapterBase.ProcessActivityAsync(String authHeader, Activity activity, BotCallbackHandler callback, CancellationToken cancellationToken)    at Microsoft.Bot.Builder.Integration.AspNet.Core.CloudAdapter.ProcessAsync(HttpRequest httpRequest, HttpResponse httpResponse, IBot bot, CancellationToken cancellationToken)    at Bot.Controllers.BotController.PostAsync(String route) in /Users/danielhjelm/Desktop/ChatBot/Bot/Bot/Controllers/BotController.cs:line 67    at lambda_method(Closure , Object )    at Microsoft.Extensions.Internal.ObjectMethodExecutorAwaitable.Awaiter.GetResult()    at Microsoft.AspNetCore.Mvc.Infrastructure.ActionMethodExecutor.AwaitableResultExecutor.Execute(IActionResultTypeMapper mapper, ObjectMethodExecutor executor, Object controller, Object[] arguments)    at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeActionMethodAsync>g__Logged|12_1(ControllerActionInvoker invoker)    at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeNextActionFilterAsync>g__Awaited|10_0(ControllerActionInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)    at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Rethrow(ActionExecutedContextSealed context)    at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.Next(State& next, Scope& scope, Object& state, Boolean& isCompleted)    at Microsoft.AspNetCore.Mvc.Infrastructure.ControllerActionInvoker.<InvokeInnerFilterAsync>g__Awaited|13_0(ControllerActionInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)    at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeFilterPipelineAsync>g__Awaited|19_0(ResourceInvoker invoker, Task lastTask, State next, Scope scope, Object state, Boolean isCompleted)    at Microsoft.AspNetCore.Mvc.Infrastructure.ResourceInvoker.<InvokeAsync>g__Logged|17_1(ResourceInvoker invoker)    at Microsoft.AspNetCore.Routing.EndpointMiddleware.<Invoke>g__AwaitRequestTask|6_0(Endpoint endpoint, Task requestTask, ILogger logger)    at Microsoft.AspNetCore.Authorization.AuthorizationMiddleware.Invoke(HttpContext context)    at Microsoft.AspNetCore.Server.IISIntegration.IISMiddleware.Invoke(HttpContext httpContext)    at Microsoft.AspNetCore.Server.Kestrel.Core.Internal.Http.HttpProtocol.ProcessRequests[TContext](IHttpApplication`1 application)

[ramfattah]

Thanks for the update and detail explanation @DanielHjelm.

Initially, I tested with QnA Intent Recognizer inside the root dialog. I can try to use the ConversationUpdate Activity to start a QA dialog to see if it reproduces the same behavior.

Will report back soon.

[DanielHjelm]

@ramfattah Any other suggestions on how to do this?