[Bender]

I ran into this with an NVMO mobile provider. They did not like my personal email domains (assorted .net and .org) so I nagged their customer support until they manually added it. Their marketing team happily emails my personal domains once added. Some day this will probably cause a problem but my goal is to eventually get rid of my cell phone either way.

[reaperducer]

I ran into this with an NVMO mobile provider.

As of about six months ago, AT&T's web site would not accept email addresses without a three-character TLD. I had to get a customer service person on the phone to manually change my address.

[toast0]

Even .us ??? Pretty sure I used my usual domain (enslaves.us) with them for wireless and california landline and u-verse.

[Bender]

Just a guess but .us does not permit whois privacy and perhaps that may be a factor but I am entirely guessing as all my domains have whois privacy enabled and they would not say why their system rejected my domains.

[inigyou]

MVNO fwiw. Mobile virtual network operator.

[Bender]

It gets worse. The FFA keep nagging me to renew my drone registration.

[badc0ffee]

Do you mean it was failing with a >3 character TLD?

[abirch]

could be < 3

   .io
   .co
   .ai

[throw0101c]

> could be < 3

Or any ccTLD: .ca, .fr, .se, etc.

* https://en.wikipedia.org/wiki/Country_code_top-level_domain

[badc0ffee]

But those have been around forever. The newer ones (.shop, .wiki, etc.) are >3 and it makes more sense to me they wouldn't be handled correctly.

[abirch]

I don't know the specifics. I can imagine someone using a regex like

^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-zA-Z]{3}$

it worked for the emails that the web dev tried and you have to have a valid email address to file a complaint.