I followed this link to add my unsubscribe email header as below,
/^Content-Transfer-Encoding:/i PREPEND List-Unsubscribe: mailto:<sender-email-address>?subject=unsubscribe>"
so that the unsubscribe requests could directly go to the sender, instead to a specific email address, such as the case at this link, where the header uses mailto:
like List-Unsubscribe: <mailto:xxxx@yourdomain.com>
But when testing my email at mailgenuis.com, I still get the issue "(-1 points) There is no List-Unsubscribe header.
"
So, is my unsubscribe header correct?