When a customer subscribes to a newsletter, an email will automatically be sent to the customer's inbox containing a link for the customer to confirm their address. This is to prevent automated spam emails and to ensure that no third party can register an email address for sending without the customer/subscriber's confirmation.

The most common reason for customers/subscribers being marked as "Pending" is that they have not clicked on this link to confirm their address. This link is created in Step 2 of the process when creating their own form

If the customer/subscriber does not click on the confirmation button, they will not become an active member. If the customer/subscriber wants to receive a new confirmation email, they can sign up again after 24 hours have passed.