[jeffmk]

With my .consulting domain, which is pretty out there as TLDs go, I've had a validation issue with just one site so far out of a dozen or so. I can't remember exactly which one, but it was some credit-card bank.

It was frustrating, but luckily I had a .com address that routes to the same email address, so it was more an annoyance than a crippling flaw.

That said I haven't given it out as an email address to humans, so have no data for reception there.

FWIW I'm using ProtonMail's professional plan, which I've found is pretty solid as a gmail replacement, if you're looking for alternatives.