Consider the following scenario:

  • You deploy a dual tone multi-frequency (DTMF) based Interactive Voice Response (IVR) application. The application is developed by using Microsoft Lync Server 2010, Unified Communications Managed API 3.0 (UCMA3.0) Workflow Speech controls.
  • The application contains a SpeechQuestionAnswerActivity and an associated ConsecutiveNoInputsSpeechEventActivity, ConsecutiveNoRecognitionsSpeechEventActivity, SpeechHelpCommandActivity, or SpeechRepeatCommandActivity. These event or command activities contain a StatementActivity or SpeechQuestionAnswerActivity.
  • A user connects to the application, and then the user starts pressing DTMF digits while a question message plays back.
  • The application stops playing the question message and stays silent, and then the user disconnects.

In this scenario, the UCMA 3.0 workflow IVR application crashes. Additionally, you receive the following error message:

System.NullReferenceException was unhandled
Message=Object reference not set to an instance of an object.
Source=System.Workflow.ComponentModel

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