The "Page not Available" error you are encountering while trying to use Speech Translation could be due to a few reasons. It's possible that the service is temporarily down or experiencing issues. You can check the status of the Nuance speech recognition system to see if there are any ongoing problems. Additionally, clearing your web browser cache and ensuring that cookies and JavaScript are enabled may help resolve the issue. If you are using Google Chrome or Mozilla Firefox, make sure to refresh the web page if you reconnect your microphone.
Kindly refer below link: troubleshooting
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