[sneak]

Lots of websites reject email addresses at entirely valid domain names as invalid, too, such as any at some of the new TLDs like .email.

[indymike]

Yep. One of our salespeople had a fit because a prospect couldn't get emails from him. The return message said "we do not accept email from the .io top level domain".

[whatatita]

So many websites provide some TLD validation but don't keep it up to date. Using .xyz is an exercise in frustration.

[ceejayoz]

I'm a little more inclined to forgive that, but dashes in the domain have been valid for decades.

[Symbiote]

Since the start, even.

bell-atl.com is one of the oldest domains still in use, registered in 1986.