The suppression list consists of email addresses that can not be added to your account and cannot receive messages from you. The suppression list can be a very useful tool for excluding email addresses from receiving your messages. There are various reasons why you might need to exclude certain email addresses from being added to your account, with the most common being to honor the request of people who have opted-out from receiving messages from you.
To add a list to the suppression list:
Note - When you remove an email address from the suppression list, all of the restrictions put in place by the suppression list are removed. This means that you can send messages to that email address and they can be added to your account. Make sure to once again get the approval of the contact to send messages to them via a subscription confirmation when you remove them from the Suppression List.