Help
What does the unknown status mean?
The check did not conclude, so ValidReach cannot say whether the address works. You are not charged for it, and the retryable field tells you whether trying again is worthwhile.
ValidReach Team · Updated 2026-10-26
Common causes
A timeout, a server that delays first contact (greylisting), a temporary provider error, or a server that does not answer mailbox checks.
What to do
Retry later. If retryable is true a later attempt may conclude. If it stays unknown, send a small test batch and watch for bounces rather than discarding the address.
In the API
is_deliverable is null for unknown and credits_used is 0. Branch on status rather than treating null as false.
Good to know
Unknown is honest rather than a failure: some servers never give a clear answer.