I can't visit the website through www.getfedora.org but I can visit it at the bare domain (without the "www."). Both ways should work.

My browser says this: "Hmm. We’re having trouble finding that site."/"We can’t connect to the server at www.getfedora.org."/"If that address is correct . . . .". It doesn't matter if I type the protocol.

In ye olde days, a website was hosted only at the www subdomain while the bare domain was reserved for other purposes, such as email. But many users skipped the subdomain and went directly to the domain and expected to be served up the website like it was their dinner at a restaurant. Nowadays, when a nonexpert or an ad on the radio tells us about a website, they don't say "www" anymore, and that's one indicator of the popular preference for bare.

My web hosting service strives to be technically correct and so gives a preference to www but allows bare with not much more than a few clicks and allows having both for one site.

I don't know what other websites you manage, so I don't know what else to test, except this: While I was logged into pagure.io , www.pagure.io got me a different result without my login showing, after which the bare domain still showed my login as effective.