Level: Beginner
Correctly distinguishing bounce types, and handling each appropriately, is a foundational technical practice that directly protects sender reputation.
Hard Bounces Signal a Permanent Failure
A hard bounce indicates the recipient address doesn't exist or the domain is invalid, and continuing to send to that address repeatedly damages sender reputation.
Soft Bounces Signal a Temporary Issue
A full mailbox, a temporarily unavailable server, or a message size limit typically triggers a soft bounce, which may resolve on a later retry.
Suppression Lists Should Be Updated Automatically
Hard-bounced addresses should be removed from future sends immediately and automatically, since manual, delayed suppression leaves a reputation-damaging gap in your sending practice.
Next step: Use the Suspicious Domain Checker to check whether a bouncing domain shows other red flags before deciding how to handle its associated addresses.