What is the reason for HTTP ERROR 418?

Question

Web servers

It looks like I'm the only one with this problem, but I don't even know where to dig...
There is one site that opens (probably) from anywhere in the world, except for my work.
On all sites, I see the same thing about this error, that this is an April Fool's joke. However, from any working PC, on any browser (if you do not use anonymizers), the same error occurs. If it was a firewall, then for sure the error would be different, not http error.
But what could it be then???

Answer 1

Either you are a spammer, or your admin played a joke on you.