Unable to successfully use mstts:backgroundaudio

Whenever I use the mstts:backgroundaudio tag, an Internal Server Error is raised by the SpeechSynthesizer.

I am using the following SSML:

<speak version="1.0" xml:lang="en-US" xmlns:mstts="http://www.w3.org/2001/mstts">
  <mstts:backgroundaudio src="https://www2.cs.uic.edu/~i101/SoundFiles/StarWars3.wav" />
  <voice name="en-US-GuyNeural">
    The text provided in this document will be spoken over the background audio.
  </voice>
</speak>

The file is a reachable 1 channel pcm_s16le 22050Hz audio. But the speechSynthesis throws the following CancellationResults:

{
  "privResult": {
    "privResultId": "8C65755E71AD44C6BA49381DBD938FCF",
    "privReason": 1,
    "privErrorDetails": "Internal server error. websocket error code: 1011",
    "privProperties": {
      "privKeys": [
        "CancellationErrorCode"
      ],
      "privValues": [
        "ConnectionFailure"
      ]
    }
  }
}

Other mstts tags like mstts:express-as work as intended.

Tested on Node with microsoft-cognitiveservices-speech-sdk version 1.16.0 in the following regions:

• eastus
• westeurope

[yulin-li]

@ccoreilly The word boundary feature is disabled by default. Make sure the WordBoundary event is not subscribed is enough.

[ccoreilly]

@yulin-li can you tell me how to disable to word boundary in the Java SDK? I only managed to do it in the JavaScript SDK but not Java and it is thus blocking my usage of the tag.