If you can log in to the computer but can't get to the internet, make sure you have authenticated the browser to connect to the internet - use this link: https://auth.cdu.edu.au, then log in using your CDU credentials.
If you have tried multiple computers, take your time entering your credentials to ensure they are correct. If they are correct and you haven't updated your password for more than three months, you will need to reset your password.
If you are using your own device at a CDU campus:
Make sure you have connected to the CDU Wifi, ITMS recommend connecting to eduroam.