Why does my email bounce after I change my MX records?
Typical causes
Mail is delivered to whichever MX record a sender's server sees, so a half-finished change can split delivery between two providers. A mistyped hostname or a priority number set in the wrong order can also cause errors. Some providers need the domain verified in their own system before they accept mail.
- A typo in the mail server hostname
- Old MX records still pointing at a previous provider
- Mailbox not created or domain not verified in the new service
- Priority values set in the wrong order
Testing the new setup
Run an MX lookup from a DNS tool to see what the public internet currently returns. Send a test message from an outside account and read the bounce text, since it usually names the rejecting server and the reason. Compare that message with your provider's error guide.
Avoiding gaps
Keep the old provider active until the new one is confirmed working, so no messages are lost in between. Lowering the TTL a day ahead, when your DNS host allows it, helps the switch happen faster. Recheck spam authentication records after the move.
Common mistakes
- Changing MX records and cancelling the old provider the same afternoon.
- Editing records at the wrong DNS host when the nameservers point elsewhere.
- Assuming a bounce means the DNS change failed when the mailbox itself is missing.
