Bounce rate refers to the percentage of emails that fail to reach the recipient?s inbox, either due to invalid email addresses, full mailboxes, or email server issues. There are two types of bounces: hard bounces and soft bounces. A hard bounce occurs when an email is permanently undeliverable, often due to an incorrect or nonexistent address. A soft bounce is temporary, caused by issues like a full inbox or a server problem. High bounce rates can negatively impact email deliverability and sender reputation. CRM systems help monitor and reduce bounce rates by verifying email addresses, segmenting email lists, and ensuring compliance with anti-spam regulations like GDPR and CAN-SPAM. Businesses use bounce rate analysis to improve email campaigns, increase open rates, and maintain engagement with leads and customers.