# `mx_unresolvable`: the mail servers the domain points at do not exist

The domain publishes MX records, but every target fails to resolve or resolves to an address that cannot receive mail from the internet.

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

Every MX target either does not resolve, resolves to a loopback or private address (127.0.0.1, 10.x, 192.168.x), or resolves to nothing routable. Mail sent there bounces at the first hop. It is common on abandoned domains and on domains whose DNS was migrated without the mail records.

Spaw reports mx_found false and skips the handshake. Compare mx_unreachable, the smtp_reason for hosts that resolve but cannot be reached.

**What to do.** Treat the address as undeliverable. If it is your own domain, fix the MX targets; the answer refreshes once DNS caches expire.

```json
{
    "email": "ops@dead-mail.example",
    "deliverable": "undeliverable",
    "reason": "mx_unresolvable",
    "mx_found": false
}
```

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