Glossary
A hard bounce is a permanent failure caused by an invalid recipient address or non-existent mailbox. These addresses are automatically added to your suppressions list when a hard bounce occurs, preventing subsequent delivery attempts and further hard bounces.
Email delivery failures fall into two main categories:
Why it matters:
Hard bounces signal invalid or non-existent addresses to inbox service providers (ISPs). High rates of hard bounces can negatively impact your sender reputation, making ISPs less likely to place your emails in subscribers’ inboxes in the future.
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