If you notice high complaint rates, take immediate action: 1. Analyze Feedback: Look at the feedback and complaints to understand the root cause. 2. Audit Your Content: Review your email content for relevance, value, and frequency. 3. List Hygiene: Clean your email list to remove inactive or non-engaged subscribers. 4. Consult Your ESP: Reach out to your email service provider for advice and best practices. 5. Re-engagement Campaigns: Run re-engagement campaigns to win back inactive subscribers or to confirm their interest in your emails.