When I use the Excused Absence Extension page (Mac Chrome, not sure it matters)
and I select a valid homework, enter a valid student and a number of days late
(leaving the date field blank) I get an error. This used to work....
In order to enter an extension I have to enter the extension by manually chosing the
date the desired number of days after the deadline.

The original design was

Add Sentry error monitoring via the PHP sdk https://docs.sentry.io/platforms/php/