Recovering a domain's email reputation after a spam attack and subsequent block, especially on Gmail, requires a comprehensive strategy that combines technical remediation, proactive engagement, and ongoing monitoring. Immediately address any security vulnerabilities that led to the attack and ensure that compromised systems are secured. Implement robust email authentication (SPF, DKIM, DMARC) and strictly adhere to email sending best practices and Gmail's guidelines. Proactive measures include list hygiene (removing inactive subscribers), warming up IP addresses or migrating to a new one, and segmenting audiences for targeted messaging. Monitor key deliverability metrics like bounce rates and spam complaints and engage with postmasters, ISPs, and potentially Google through their escalation form (although its effectiveness is debated). Consider blacklists and whitelisting opportunities. Ongoing positive sending behavior and a commitment to responsible email practices are crucial for rebuilding trust and long-term deliverability.