The employee's User Account may be lock if:
- the employee resigned
- the employee is suspended
To lock, click the profile icon in the upper-right corner of the page, go to Administration - User Management - edit employee.
You will see that the Active box is ticked.
Untick the Active box then tick the Locked box.
Once done, click Update below.
A pop-up confirmation message will show, click YES to proceed.

Another pop-up confirmation message will show that you successfully updated user.
In User Management, updated user account will now show as LOCKED.