This error in Azure Pronunciation Assessment typically indicates an issue with the configuration or the way the speech context is being set up. Here are a few common reasons and potential solutions:
Ensure that the configuration parameters for the pronunciation assessment are correctly set. Double-check the settings for PronunciationAssessmentConfig and make sure they match the expected format.
Verify that you are using a compatible version of the Azure Speech SDK. Sometimes, using an outdated version can cause deserialization issues1.
Ensure that the audio format of the input file is supported by the service. The service typically supports WAV files with a sample rate of 16 kHz3.
Subscription Key and Region: Make sure that your subscription key and service region are correctly set in your configuration. Incorrect credentials can lead to errors.
Implement robust error handling in your code to catch and diagnose issues more effectively.