Hello @stephen Makumbi , Thanks for using Microsoft Q&A Platform.
Try to make sure that the 'Microsoft.CognitiveServices.Speech.core.dll' file / dependencies are included in the published folder. You can also try restarting and see if that resolves the issue.
Here are the similar issues you can refer to: https://github.com/Azure-Samples/cognitive-services-speech-sdk/issues/1636
https://github.com/Azure-Samples/cognitive-services-speech-sdk/issues/2002
If you still face issue, please raise it here: https://github.com/Azure-Samples/cognitive-services-speech-sdk/issues
I hope this helps.
Regards,
Vasavi
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