When you said earlier that you generated a new certificate, how did you do that? Via the printer’s embedded web server?
It’s weird that HP’s Mac instructions specify using a Windows computer to perform the change. Even stranger is that I’ve seen some posts in the HP support forum that suggests generation fails with Chrome but works with Firefox. Maybe they didn’t want to get into explaining to Mac users how to access and override expired certificates with different Mac browsers.
HP also suggests using their “HP Smart” app on the Mac, though I personally try to avoid using that whenever I can.
