You included a text or button link in your email design that linked to an email address so that recipients can click to send you an email. After the campaign is sent, you don't see any click tracking for that link. Why?

The answer is that "mailto" links are not tracked in reporting for campaigns. The reason is that it's not a standard web URL, it does not open a browser page. Because of this, it's not wrapped with tracking tags in the system.