It's possible you haven't updated it in the last 30 days: there are certain card readers around the campus that automatically update your card every time you use them; the card units at the entrance to the Library and 24/7 IT Suite are this type of reader.
If you update your card at these units and it still doesn't work, it's likely that the card has become inactive. If this happens please go to the Security Office in the Hardy Building.
