Handling bounces, auto-replies, and loops
To stop mail loops, the inbound engine recognises and discards bounces and automated replies before they can create tickets.
What gets suppressed
A message is ignored if the sender address contains any of these fragments:
mailer-daemon,postmaster,bounceno-reply/noreply,do-not-reply/donotreply
…or if the subject contains any of:
delivery status notification,undeliverableauto-reply,automatic reply,out of office
Why it matters
Because the app auto-acknowledges new portal and email tickets, an auto-reply (such as an out-of-office) sent back to that acknowledgement could otherwise loop endlessly. Suppression breaks the cycle: a matched message is logged as ignored and no ticket or reply is created.
Mailgun webhook responses
The Mailgun webhook returns status codes that align with Mailgun's retry semantics:
| Code | Meaning |
|---|---|
200 | Processed, deduped, or ignored — Mailgun stops. |
406 | Bad/forged signature — permanent drop. |
503 | Signing key or account not configured yet — retried. |
500 | Transient processing error — retried. |
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