When a subscriber signs up for your AWeber list, and you have confirmation enabled, they will receive a confirmation message. The confirmation message is valid for 30 days from the time the subscriber was initially sent the message.
If a subscriber keeps the confirmation message in their inbox for 30 days and does not confirm by clicking the button, the message will become invalid. For these situations, the subscriber will see the following notice:
What can I do if someone reports that their confirmation message is invalid?
If a subscriber reports an invalid confirmation message, direct them to sign up again for the list again. Additionally, be sure to let him or her know there is a 30 day window to confirm the subscription to the list. If the subscriber was added through an application rather than a form, you can direct them to sign up for your list through the hosted URL of your AWeber form.