Suppressions
The Suppressions tab displays any addresses that will be omitted from future messages.
Email addresses are automatically added to the suppressions list when:
A hard bounce occurs (bad address, mailbox does not exist, etc.)
The user click the “unsubscribe” link within the email or the header of their email software.
The user reports the message as spam to their email service provider.
If you believe that a user has been added to the suppression list in error, you can manually remove them by clicking on the “Remove Suppression” button: