Inbound mail diagnostics

Fix a Null MX email rejection

A standalone Null MX is a valid declaration that a domain does not accept email. It is a conflict only when that domain is explicitly meant to receive mail.

Problem description

MX 0 .

Check mail-receiving intent free

What the result means

Mixed Null MX and ordinary MX records are invalid. A single Null MX remains intentional for an outbound-only or no-mail domain.

Safe repair

Change DNS only after confirming that inbound email is required, then use the exact MX records issued by the receiving provider.