List-Unsubscribe Header Not Showing Up in Emails


Issue Description
You have sent an email and do not see the List-Unsubscribe headers.



Issue Resolution
Marketo automatically adds the appropriate List-Unsubscribe headers to emails, EXCEPT in three scenarios:


1) The email is marked as operational

2) You are sending a test email via the "Send Sample" action

3) The email is an alert email


In these cases, the List-Unsubscribe header will not be added to the email.