Email Integration Question

Content

When setting up an enrollment and then sending a meeting request through the learn center, we would like to track who has accepted, declined, not responded, etc., the enrollment.  The email makes it to those we enrolled, and as the administrator we see the accept and decline responses in our inbox.  However, when we go to the calendar and open up the meeting request the tracking button isn't displayed for us to be able to see who has accepted, declined, or not responded.  Does anyone know how to display the tracking button?  We use this button all the time outside