Before you dispose of your token, check if it is just out of sync. You may be able to re-sync it by attempting to log in three times in a row, with a new code each time. If that still fails after the third attempt, contact Technology Help.
Why do tokens get out of sync?
The codes that tokens generate can become out of sync with the Duo authentication system. If you keep your token in a pocket or on a keyring - or if you have someone in your life who likes to press buttons - your token may get out of sync because
the button was pressed repeatedly over a short period of time
the token generated numbers that were not used
the token was not used for over a month
the battery is dying (token batteries generally last between 2 and 5 years)