Ran the developer tools on the Windows 11 machine and see the following in the Console tab:
HTML1527: DOCTYPE expected. Consider adding a valid HTML5 doctype: "<!DOCTYPE html>".
Ran the developer tools on the Windows 10 machine and see the same message in the Console tab.
Also, when Navigating in the website on the W11 machine, I get the attached message - if I click more info, it takes me to the Java website to install Java - which I have already done.