Sometimes if you add an email template mask, like #RatingLinks# or #WhatHappened# or #Category# - you may find it's not working.
It is possible that the email template HTML is malformed, causing the #Mask# tag to not display properly. To check for hidden symbols or formatting issues, switch to the source code view in the template editor. Click the "</>" button to access the source code and review the markup for any anomalies.