Why is the unsubscribe link in the footer not working?

The unsubscribe link is made available to contacts who wish to permanently remove themselves from your mailing list(s). Sometimes, though, this link may not function correctly. If the unsubscribe link is not working, it may be due to: The email client being used by your contact not processing the link properly. The contact using a text-only email program, which requires that they copy and paste the link into a web