450 4.7.1 Greylisted, see http://postgrey.schweikert.ch/help/example.com.html
Sample bounce line
450 4.7.1 Greylisted, see http://postgrey.schweikert.ch/help/example.com.html
What it means
Postgrey, a Postfix policy service, temporarily rejected the message because this client IP, sender and recipient combination had not been seen before or was seen less than 5 minutes ago. It is a temporary (4xx) failure: a compliant server queues the message and retries, and the retry is accepted after the delay.
Why it happens
- First contact from this sending IP, sender and recipient combination (Postgrey site: a first-seen or under-5-minutes-old triplet is rejected with a temporary error)
- The retry came too early or from a different sending IP than the first attempt
How to fix it
- Sender: do nothing special; a standards-compliant mail server retries automatically and the retry succeeds once the delay has passed
- If you see this when sending from a mail client, the Postgrey help page says to make sure encryption and authentication are turned on for the SMTP server in the client
- Postgrey admin: the source defaults are --delay 300 seconds, --retry-window 2 days and --max-age 35 days; trusted senders can be added to a client whitelist (postgrey_whitelist_clients is shipped in the official pub directory)
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Related errors
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