Symptom: spamreport events climbing per campaign.
Cause candidates:
1. Mailing people who did not ask for mail, or kept mailing long-inactive addresses.
2. No visible, working unsubscribe. People who cannot find the opt-out use the spam button instead.
3. Content/subject mismatch with what the recipient signed up for.
Confirmation: join spamreport events to the campaign and list source. One bad list import usually explains a spike.
Fix:
1. Suppress every spam reporter immediately and permanently. Never mail them again.
2. Make the unsubscribe obvious and one click from the mail. The doc requires an opt-out; burying it manufactures spam reports.
3. Re-confirm or sunset unengaged segments. If they have not opened in months, stop mailing them.
4. Check that the from name and subject honestly describe the content.
Verification: spamreport rate per thousand delivered falls back to baseline on subsequent campaigns. If it does not, the list source is still bad.