Okay, the Rookie is back.
We went live with ITSM on 6/1/17. We were able to reply by email when when a task was assigned or CAB approval was required for a Change by repling with "Accepted", "Denied", etc. It seems that since when we upgraded from 2016.1 to 2017.2, this function has stopped working. I've been searching config and admin manuals, but I not finding the information I need. Any advice.