Glossary/Email & Lifecycle/Hard Bounce
Email & Lifecycle
Hard Bounce
A permanent email delivery failure, such as an invalid or nonexistent address, that should be removed from the list immediately.
By Brandon Mina·CEO, BrandPilot AI·Updated November 2026
Short answer
A hard bounce is a permanent email delivery failure, typically caused by an invalid, misspelled or nonexistent address or a domain that does not exist. Hard-bounced addresses should be removed from mailing lists immediately. Continuing to send to them damages sender reputation and can push future emails into spam folders.