What to do when a result is not what you expected: why a valid address can bounce, and why a working one can show invalid.
An address shows valid but bounces
Possible reasons:
- Accepted, then bounced - Some servers accept an address during the check and bounce the message later
- Full mailbox - Mailbox was full at delivery time
- Greylisting - Temporary rejection
- Recent change - Mailbox deleted after verification
An address shows invalid but its owner says it works
Possible reasons:
- Anti-harvesting filters - The server answers checks it does not trust with the same reply it gives a missing mailbox
- Recent change - Mailbox created after verification
- Custom mail setup - Non-standard configuration
A server that blocks our check is reported as risky with policy_block, not as invalid.
What to do
- Re-verify the email (results may differ)
- Check the detailed response fields
- Look at the quality score, not just status
- Consider the domain type (corporate vs. free)
Reporting issues
If you consistently see incorrect results, contact support@kawaa.com with:
- Email address(es) in question
- Expected vs. actual result
- Evidence (bounce message, user confirmation)