Why am I receiving emails from the postmaster after a mailing?

Some recipients’ mail servers accept an email and only later decide whether to deliver it. Even if Boldem reports the email as delivered, it may later turn out that delivery wasn’t possible (for example because the mailbox doesn’t exist or is full). Boldem isn’t notified about these cases because the recipient’s mail server sends so‑called DSN (Delivery Status Notification) messages to the sender’s email address.

How do I fix this problem?

1. Dispatch from a subdomain: Set the subdomain for email deliveries (e.g. info@novinky.example.cz) and correctly configure DNS records.
2. MX record settings: For the subdomain, set the MX record to bounce.boldem.cz so DSN messages are processed directly by Boldem.
3. Manual contact management: If you don’t want to automate processing of DSN messages as described above, you must update contacts in Boldem each time you receive a delivery failure notice (e.g., permanently unsubscribe nonexistent addresses) to prevent repeated sending.

You can find more details in the chapter Troubleshooting deliverability – Postmaster reports.