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
- credits
- Free. Undeliverable verdicts never cost a credit.
What it means
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.
Example response
{
"email": "[email protected]",
"deliverable": "undeliverable",
"reason": "mx_unresolvable",
"mx_found": false
}Abbreviated: a real answer carries all 27 fields, listed in the verify-email reference.
Related
- invalid_syntax · the input does not parse as an email address
- invalid_local_part · the username breaks the rules its own provider enforces
- no_mx_records · the domain has no mail servers at all
- null_mx · the domain declares that it never accepts mail
- mailbox_not_found · the mail server rejected the mailbox during the handshake
- mailbox_disabled · the mailbox exists but its provider has disabled it
- suppressed · the address is on your account's suppression list
- All verdict reasons
- Verdicts and the risk score
- API reference
markdown version: /docs/reasons/mx_unresolvable.md