Bounce handling refers to the management of undelivered emails in CRM and email marketing campaigns. Bounced emails can be categorized as hard bounces (permanently undeliverable) or soft bounces (temporarily undeliverable due to server issues or full inboxes). CRMs track bounce rates, automatically remove invalid email addresses, and implement re-engagement strategies. Effective bounce handling improves email deliverability, enhances sender reputation, and ensures that marketing messages reach the right audience.