When an email hard bounces, it signifies a permanent delivery failure. The first step is often analyzing the bounce code to determine the cause, ranging from invalid addresses to blocked domains. Immediate action includes removing the address from your mailing list to protect sender reputation, as repeated attempts harm deliverability. Verification steps involve confirming user subscription, checking for typos, and reaching out through alternative channels. Technical solutions include employing suppression lists, feedback loops with ISPs, list segmentation, and implementing email authentication protocols like SPF, DKIM, and DMARC. In some cases, 'dot' or 'plus' tricks with Gmail addresses might bypass suppression if the platform doesn't normalize addresses. Finally, ensure good list hygiene through double opt-in and regular cleansing.