If you've added employees as an HR admin, make sure you view employees with the same role. Changing your role to "Employee" or "Manager" won't allow you to view all employees.
To switch role, go to the Role and Features menu and pick your preferred role from the Select role dropdown. If you're currently an "Employee" and need to see all employees, switch back to "HR admin" role.
P.S. HR admin/ Director/ CEO are the roles assigned to the enrollee, depending upon the designation they selected in the initial setup.