Your FalconNet password requires that you change it once every calendar year. You can change this password in several different ways, however, if you change it when you are off-campus and not connected to the local network, your laptop will not be notified of this password change. Your laptop caches any password that you use to login that is certified by the local server. If you are not connected to the local network when you login, your laptop will not check the password (for 45 days), and will not recognize your new password as being valid until you come to campus, plug in, and login again.
Here's how your fix it: