SimpleVerifier Team · Reviewed
Why does a verified email still bounce?
A verification result is a snapshot. The mailbox may have closed since the check, be full, or sit at a catch-all domain that accepted it and bounced later. The bounce can also come from your side: a blocklisted domain, failing authentication or a reputation problem produces rejections that have nothing to do with the address.
Common causes, most likely first
The usual causes, in the order we see them.
- The result was risky, not valid, and was sent anyway.
- The result is old: mailboxes close, and SimpleVerifier re-checks results older than 14 days.
- Temporary failure such as a full mailbox, which is a soft bounce.
- Your domain or IP is blocklisted, or SPF, DKIM or DMARC fails: a 5.7.x code, not an unknown-mailbox code.
How to tell
Read the bounce code. 550 5.1.1 is a missing mailbox; 5.7.x codes are policy and reputation. The bounce message analyzer explains a pasted message.
Related questions
- What bounce rate is normal after verifying?
- Usually far below an unverified list, but not zero. The remaining bounces come from the causes above.
Sources
Figures marked as ours come from SimpleVerifier’s own dated tests on made-up addresses, published with their data on the research page. No customer data is used, and we publish no accuracy percentage because we have no independent measurement to back one.
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