product · inferred from evidence
KB5020435
An out-of-band Windows update for Windows 10 versions 20H2 through 22H2.
- Azure text to speech timeouts: WS_OPEN_ERROR_UNDERLYING_IO_OPEN_FAILED after Windows update
We confirmed this is caused by the October 2022 Windows security updates, which changed TLS behavior and broke the SDK connection to the TTS service. The fix is to install the out of band update for your build: KB5020435 for Windows 10 20H2