Symptoms:
Web TimeSheet sends all the other e-mail notifications however, fails to send only the Timesheet is due notification. All the settings (email notification is enabled for the user and other settings are correct).

Cause:
The Timesheet is due notification is sent to users to remind them that they are due for timesheet submission. This e-mail notification is not triggered for the timesheet users who have submitted the timesheet before the due date, and time set for the email notification.

Note:
Timesheet is due notification is triggered for the timesheet users whose timesheets have not been submitted until the due date, and time set for the email notification.