Mail bounces and the bounce mailbox
What a subscriber’s “Mail bounced” status means, how the site learns about undelivered letters and how to set up the bounce mailbox.
When a letter does not arrive (there is no such address, the mailbox is full), the mail server sends back a bounce. The site reads these reports and stops writing to dead addresses, so as not to spoil your sender's reputation.
How it works
- A hard bounce (codes 5.x.x, for example “no such address”) at once moves the subscriber to “Mail bounced”: letters no longer go to them.
- Soft bounces (4.x.x, a temporary fault) pile up: three in 30 days also mean “Mail bounced”.
- A report without our signed tag is only written down and does not count: forged reports cannot switch off other people's subscribers.
- Once an hour the site reads the bounce mailbox, marking the letters as read; it deletes nothing.
How to set it up
In “Site settings → Mail → Bounce mailbox (optional)”. Empty by default, and then nothing happens.
- Bounce address — a separate mailbox on the same domain as the sender. Do not use your work or personal mailbox.
- Personal return address per subscriber (VERP) — on by default; it lets a bounce be tied to a particular subscriber.
- IMAP server, port (993), login, password (stored encrypted) and folder.
Where to look
- In “Newsletter → Overview”: “Mailbox for bounces: time and result of the last check”.
- In “Newsletter → Subscribers”: the address has the “Mail bounced” status and the “Return to subscribers” button to restore it by hand.