[MadQA]

Have you tried to check https://postmaster.google.com/? You _may_ get an insight on what went wrong those 3 months ago

[kuschku]

That requires hundreds or thousands of emails from your domain per day to show anything - which is useful if you run a major service, but for the use case of "every person hosts their own email", it’s not exactly useful.

[MadQA]

Well, you're right, though I've seen data in there for domains with about 10k emails per month.

Still, that's probably way over the home email setup threshold.