Mine is “first name at last name dot dk, only last name is spelled with an ‘O’ instead of an ‘Ø’” ...

It’s quite common when giving my email over the phone that my full name has already been established so I really wished the “Ø”-version would work (I also own that domain) but most (many? Some? Too many) email clients refuse to send emails to servers that contains special characters.

I can receive emails at the ø-domain, but not send to it using Fastmail. They recommend I use puny codes but that’s way too difficult to communicate.