[abdullahkhalids]

Oh! That's what it is. I just thought some websites just took longer to send an email to my unknown domain.

I see that the only way to disable greylisting is to configure the underlying tool [1]. But it also means that SPAM will increase a lot.

[1] https://discourse.mailinabox.email/t/how-to-turn-off-edit-gr...

[behringer]

It's better to whitelist the domains you'll be getting mfa from.