I’ve seen my fair share of email delivery issues, but all being this globally shit-canned says to me is “we’re operating in some very-abused IP space and operators aren’t lining up to let us in”.

This is all assuming that the mail is otherwise ticking all the boxes. One too many times I’ve seen someone get on their HN soapbox because their $5 DigitalOcean mail server keeps getting shit-canned, only to find after some polite prodding that they just flat-out weren’t aware of the modern-day complexities of sending email.

Not to say that this is what’s happening here, of course.