Thank you Kyle. There indeed still exists Internet Explorer in Windows 10 (see attached screenshot of the Help About in Internet Explorer).
It is distinct from the new Edge. In fact, in Edge, you can visit a website, then click on the menu (...) and choose "Open with Internet Explorer" if you cannot find IE directly.
Your suggestion to change the Live_site to "" has fixed the problem.
The Live_site setting must have been a remnant from the development site.
Thank you !
Warmest regards,
Brian