[8cvor6j844qw_d6]

Do you have a recommendation for a major email provider as a fallback if you have to pick one?

I vaguely recall encountering a service that only accepted addresses from a whitelist of big providers (Gmail, Yahoo, Outlook, etc.), even @icloud did not qualify.

[JoshTriplett]

That's a service that doesn't want your business. If you care, message them about it

I've never once run into a service with such a restriction, but I can imagine someone being that short-sighted. I have seen services that only support "log in with Google or Facebook", which is comparably terrible.

[genxy]

Discogs will not let me login with my own domain (of 30 years) and required one of the big providers. It kept complaining about "risky domain". But that is the only incident I can think of.

[sir0010010]

I've run into services that will flag specific tlds as invalid.