mx_unreachable
The mail exchangers could not be reached from the verification network
The probe could not reach any of the domain's mail servers: unreachable at the network level rather than a refused connection.
- appears in
- smtp_reason
- credits
- Free: an answer the mailbox check could not settle costs nothing and leaves no 7-day repeat marker; the settling re-checks bill 1 credit only when they confirm the mailbox. A verdict another signal decides, such as role, bills 1 credit as that verdict.
What it means
Transient routing problems and geo-restricted mail servers produce it. The answer is not cached for long, so a later lookup probes again.
What to do
Pass callback_url with the lookup: Spaw re-checks the address after 5 and 20 minutes and pushes the settled verdict to you, billing 1 credit only if a re-check confirms the mailbox. Or re-verify later: an unverified answer leaves no repeat marker, so once its 15-minute probe result has expired the next lookup asks the server again.
Example response
{
"deliverable": "risky",
"reason": "unverified",
"smtp_checked": false,
"smtp_reason": "mx_unreachable",
"mailbox_exists": null
}Abbreviated: a real answer carries all 46 fields, listed in the verify-email reference.
Related
- no_mailbox · the server answered that the mailbox does not exist
- disabled · the server reported the mailbox as disabled or suspended
- greylisted · the server deferred the handshake and asked the sender to come back later
- timeout · the mail server did not answer within the probe's time limit
- no_connect · no mail server accepted a connection on port 25
- delivered_recently · your own delivery report confirmed this mailbox
- provider_unavailable · the verification provider itself could not answer
- All verdict reasons
- Verdicts and the risk score
- API reference
markdown version: /docs/reasons/mx_unreachable.md