When it says ‘password NOT changed’, it usually means you are not meeting the criteria for the password.
Check the Enterprise Portal to see if in the Admin section/System page Password Management has been Enabled and enforcing Complexity is Enabled.
The criteria for the password at the TeamWork Learning Center: Enterprise Portal Help Card/Getting Started/#3 Passwords.
If the users and employees are being required to change their password after a certain number of days, when they try to logon, they will get the notice below, showing the requirements for complexity:
If no repeats is enabled, they will not be able to use any password they have used in the past.