The AUMID shown in this guide is incorrect. Per the instructions found at https://docs.microsoft.com/en-us/windows/configuration/find-the-application-user-model-id-of-an-installed-app, the AUMID should be the "packagefamilyname"+"!"+"package.applications.application.id". In the case of the Kiosk Bowser, the AUMID is "Microsoft.KioskBrowser_8wekyb3d8bbwe!App". Failure to include the "!App" will result in an error when the kiosk account tries to load the app.