If an employee is given a temporary password then they will need to change their password when they next log in. If they do not have access to change their own password, they will see an Invalid credentials error message. You can check if an employee has access to change their own password in WinTMS. Similarly, a supervisor may not have access to change their own password.
Enable Change Password for employees
Go to System->Employee profiles
Double click the profile the employee uses
Click Menu rights
Expand Web module->Employee
Check that Change Password is ticked
Enable Change Password for supervisorsLog into WinTMS