MX_MAIL_NOT_ACCEPTED

error

Mail sent to this domain cannot be delivered anywhere.

Something is wrong and mail or certificates are affected.

How we know

mx.test
The same records are correct or broken depending on what the domain is for: nomail is a deliberate null MX, and the only difference between the passing and failing cases is what the caller says the domain does. Also carries the exchanges that cannot receive anything — an address written where a name belongs, an alias RFC 2181 forbids, a name with no address — plus an IPv6-only exchange, which is legitimate and would be failed by a check that reads a missing A record as a missing address.