When you say it's the "Trend Micro Password Manager old password" does it mean you are referring to the master password? Kindly provide us the steps on how you try and login to the Password Manager for us to verify. :)
Just in case you would like to update your Master Password, please login on this link. Click on the Sign In button at the upper right, enter your master password, click on your account name at the upper right > choose Settings. Go to the Master Password tab and click on "Change your Master Password" button.
It may also be possible that you have a different account for the Password Manager (it's just possible but rarely happens).