Visual Studio Code Extension Can't Access Files

After installing the Visual Studio Code Extension and opening the link from the Universal instance’s configuration page, Code reports a 404 error on every attempt to see any of the script files in my environment. There is nothing in the extension log, and no errors in the Extension Host log.
I created a new Administrator token and the same behavior results when using it. There doesn’t seem to be any other configuration to check. Can there be a problem with NTFS security? The universal scripts are in the default location and the App Pool is using LocalSystem.

Product: PowerShell Universal
Version: 3.7.14