Yep, I checked other, established .zip domains. Finding one was quite a hard task, which gave me pause. I found a link shortener site on some Google promotional page for .zip (.zip is a Google-TLD). Accessing any .zip url was denied on the tested machines.
So this matches what IT told me and what the sister comments state here: some tool blocks the whole .zip TLD on the DNS level.
Tip: “nic.TLD” should always exist and will often be the first domain registered. It is operated by the domain’s registry. For example, see https://nic.zip.
So this matches what IT told me and what the sister comments state here: some tool blocks the whole .zip TLD on the DNS level.