As many have reported, currently the Text to Speech feature, which is available to users who have a VEGAS 365 subscription, is not working for many people.
This problem occurs on Windows 10 (latest) and Windows 11 (21H2) machines. The issue has to do with a specific windows update which has rolled out recently. The cognitive services used for the Text to Speech feature is also from Microsoft, like Windows, and the update specifically broke this feature. Other developers who use this service also are experiencing this problem.
Microsoft was informed of this problem and has been working on a solution to the problem. The problem was introduced by patch KB5018418 for Windows 11, and KB5018410 on Windows 10. We have instructed people to temporarily uninstall these patches to remedy the problem. Microsoft has also released fixes for this as well which can be accessed here: https://www.catalog.update.microsoft.com.
The chart below shows what patches can be installed to remedy the problem. These patches will be distributed in a future Windows update.
Windows 10 20H1 thru 21H2 KB5020435 Windows 10 1909 KB5020437 Windows 10 1809 KB5020438 Windows 11 21H2 KB5020387