By default, the Access Education People software does not allow duplicated employee numbers to be created. Each employee will need their own unique number.
This setting can be found by following the steps below:
Go to Setup and click Settings.
Click System Settings, then Global.
Search for Employee Number is Unique.
The description will state 'This check is always enabled, all employments must have a unique employee number.'
Below is how this setting needs to look like in order for the system to be correctly set up:

