In order to protect your sender reputation, and help prevent malicious sign-ups, you should get permission from your contacts before sending them any email marketing campaigns. In many places, this is required by law.
When you turn on double opt-in for your Big Commerce subscribers, we send them an email to confirm their willingness to receive email marketing campaigns from you. These contacts’ email addresses stay in a pending state until they verify that they want to opt-in.
Enable double opt-in
In Dotdigital, go to Connect and select the BigCommerce tile under Installed integrations and extensions.
Under the heading Contacts, for Enforce double opt-in for subscribers, select YES.
Select SAVE.