Checked before it sends
An address we have never delivered to is checked before the first email. If it is invalid, the send is cancelled, the person is stopped, and the address goes on your do-not-contact list without hurting your inbox.
Unconfirmed addresses
Many companies accept mail for any address, so no checker can tell whether one is real. An address counts as confirmed when a data provider or the checker vouched for it, the company publishes it on its own website, or an email to it was delivered before. Agent never emails an unconfirmed address; it waits in Tasks for you, marked Not confirmed.
When an email bounces
Every bounce stops that person and slows the inbox warm-up by one stage. A hard bounce also adds the address to do-not-contact, and after one at a company, unconfirmed addresses there are refused. Three bounces in a week pause the inbox and we email you; Resume restarts its warm-up.
Your do-not-contact list
Find it from Campaigns. Add an email or a whole company domain to make sure nobody in your workspace contacts them. People are added automatically when they unsubscribe, reply that they are not interested, hard-bounce, or you choose Do not contact on a person. Opting someone out stops every campaign still messaging them and keeps their replies.