The SpamCop domain listing and blocking in January 2021 stemmed from a domain expiration, resulting in a temporary outage and causing the service to list everything and become unreachable. After renewal, DNS propagation delays, influenced by TTL settings and DNS caching, caused inconsistent website access for users. Even after resolution, cached negative responses led to continued email bounces. Proactive domain monitoring, maintaining DNS health, prompt updates, and IP warming are crucial for preventing and mitigating such issues, and managing sender reputation is essential for recovery.