Marketo Not Appending the Unsubscribe Link Automatically

Issue

The standard unsubscribe footer shown in Admin > Email is not being appended to a particular email.

Solution

Issue Resolution
This can happen when an email contains the system token unsubscribe link:  {{system.unsubscribeLink}}

When an email contains this token, Marketo does not automatically append the unsubscribe HTML snippet, found at Admin > Email > Unsubscribe HTML.

Check the HTML of the email asset with this behavior. Search the text version of the email. You may find the {{system.unsubscribeLink}} in the template you are using.

If you have searched the HTML of the email, and are not seeing the system token, contact Marketo Support.