The site is periodically not pulling up at all on Firefox on my PC, but I have no problem accessing it on Chrome on my Droid.
I have Firefox 84.0.1 (which I believe is the latest version, I just updated) and I have Windows 10 which I keep up-to-date. I have no problems. Are you fully updated?
Also, see if you can temporarily disable add-ons, then try the site again. If it’s fine, enable them again one at a time and test the site after each one, and see if enabling one causes it to fail.