Interpretation
Use timestamps, queue IDs, remote responses, source IP, VMTA, sender domain and message class to establish the failure boundary. Avoid reacting to one isolated delivery attempt.
Review
- Postmaster Tools reputation and spam rate
- DKIM/SPF/DMARC alignment
- One-click unsubscribe where applicable
- Complaint, bounce and engagement trends
- Volume consistency by source IP and domain
Response
Reduce low-engagement traffic first, preserve steady high-quality volume, and avoid rotating to new IPs as a shortcut.
Operational rule: collect evidence before changing policy, make one controlled change, verify the result, and retain a rollback path.