Why aren't some of my employee's receiving notifications

If you are wanting some of your employee's to be receiving notifications but they are not, you can enable this under the users. Click on the gear icon next to your name and select users.

This will bring up a list of everyone on the portal. Once you are here, select the user that you want to enable notifications on by clicking the pen icon at the end of their name. 

Toggle 'Send Request Notifications Daily' to 'YES' and you will have enabled notifications to be sent to that employee.