# `null_mx`: the domain declares that it never accepts mail

The domain publishes a null MX record, the standard way of saying it does not receive email.

- Appears in: `reason`
- Verdict: undeliverable
- Billing: Free. Undeliverable verdicts never cost a credit.

RFC 7505 lets a domain publish a single MX record pointing at "." with priority 0, the null MX, to state explicitly that it does not receive email. Website-only domains, brand-protection domains and parked domains use it.

It is a deliberate, authoritative statement, so Spaw does not try the address-record fallback and does not probe. mx_found is false.

**What to do.** Reject the address. There is no correction to suggest, and nothing changes unless the domain owner removes the record.

```json
{
    "email": "hello@brand-holding.example",
    "deliverable": "undeliverable",
    "reason": "null_mx",
    "mx_found": false
}
```

Reference: https://spaw.co/docs/reasons/null_mx