Having the ability to unsubscribe from a marketing email, is required by regulations such as CAN-SPAM. However, unsubscribing accidentally via a forwarded email, or antivirus/firewall software can affect your delivery. As a result, we're making an update to the unsubscribe process for emails you send from HubSpot.
We've recently adjusted the unsubscribe process by adding a confirmation step for email recipients. When someone clicks on the unsubscribe link in an email they’ll now see a page where they must confirm that they want to unsubscribe instead of automatically being removed from all mailing lists.
After they confirm, they'll be brought to the unsubscribe confirmation page.
This change will alleviate the chance someone is unsubscribed accidentally by a firewall/anti-virus package, or by the recipient of a forwarded email. This change will begin to roll on 12/22/16 and continue over the next couple weeks for all customers.