There are two kinds. A hard bounce means the address does not exist. A soft bounce means a full inbox or a temporary problem. Hard bounces are the ones that hurt reputation.
Buzzlist watches every mailbox. After 20 or more sends in 7 days, a bounce rate of 5 percent pauses that mailbox automatically until the list is cleaned. A single spam complaint pauses it at once.
The best way to keep bounces low is to send to checked addresses. On Growth and Scale, work emails carry a verification status so you can leave out the risky ones before sending.
