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Deliverability Letter

Bounce (Hard)

Hard bounce is when an email cannot be delivered because the address is invalid or blocked. It is a permanent failure and the address should be removed from your list.

Hard bounce is when an email cannot be delivered at all. The address is wrong, no longer exists, or the server has fully blocked it. The email service marks this as a permanent failure. Sending to that address again will not work.

Hard bounces hurt your sender reputation over time. If you keep emailing dead addresses, inbox providers start to trust you less. That can push more of your messages into spam for everyone. Cleaning out hard bounces keeps your list healthy and your emails in the inbox.

Most good email tools stop sending to an address after a hard bounce, but it is still smart to review these contacts. Remove them from your active lists and check how they got there in the first place. If you see many hard bounces from one source, pause that source and fix the issue.