DIAGNOSTIC PLAYBOOK
No blocklist listing, but email is still rejected
A clean public blocklist check does not establish that every receiver trusts the sender. Providers use private reputation and policy signals that may not appear on public DNS-based lists.
HealthCheck Email editorial team · · Examples are illustrative
How to investigate
- Preserve the destination's full rejection text and any linked troubleshooting guidance.
- Check authentication, recipient consent, sending patterns and provider-specific reputation data.
- Use the receiver's supported escalation path with a reproducible sample if the cause remains unclear.
What this looks like
ILLUSTRATIVE EXAMPLE
A domain is absent from the public lists you checked, yet a receiver rejects it under an internal reputation policy.
A mistake to avoid
Do not report the sender as universally clean based on a limited list set. State which checks were performed and when.
Keep the result in context
A successful handoff, a delivered event and an inbox placement are different observations. Record the receiving provider, send time, SMTP response and affected stream before comparing results. DNS fixes address authentication or routing; they cannot establish consent or guarantee placement.
Take the next step
Use the related check to gather evidence, then compare it with the affected message or service. Keep the result and time with your notes so a later change can be distinguished from the original problem.
Sources and further reading
The protocol references below explain the underlying behavior. Your sending or DNS provider supplies the account-specific settings for its service.