Since the 10/20/2017 update, emails are not being sent to parents for Gradebook Alert Thresholds.
Unfortunately, this was only recently brought to our attention. There are no error messages, so customers would likely not be aware of the issue unless parents have reported missing email alerts that they should have received.
Programming is aware of the issue, and a fix is expected in an upcoming update. We apologize for any inconvenience this issue may have caused.
FIXED in the Aeries update dated 2/9/2018: