How to lower complaint rate

You got Sustained reported complaint rate is elevated or above 0.1%. This uses ISP feedback-loop complaints only, as a share of delivered mail, across consecutive windows with enough volume.

It is not a complete inbox-placement score. Missing ISP coverage is not treated as a clean list.

0.1% is an error. ~0.08% is a warning. Inbox providers treat complaint rate as a primary reputation signal.

What to change

1. Open Settings → Deliverability and inspect complaint windows.
2. Pause broad campaigns until you know who complained.
3. Make unsubscribe obvious and one-click. Buried unsubscribes become spam clicks.
4. Send to people who asked — drop purchased lists, old co-reg, and stale imports.
5. Tighten the audience: recent openers/clickers, or a confirmed segment, not the whole database.
6. Check subject/preview vs body. Surprise promo on a “receipt-looking” subject drives complaints.

Complained addresses are suppressed. Do not re-add them.

After it recovers

The alert resolves after consecutive adequate windows stay below the warning threshold. Keep sending only to engaged, opted-in subscribers.

Related

• How to lower bounce rate
• Content Deliverability Checker
• Sender Health