Try these steps:
1. Verify that the spelling matches exactly. Make sure that there are no spaces left over in your code. We recommend manually typing in your coupon code. This is because sometimes when cutting and pasting, there is an extra space left before or after the code, causing it to be invalid.
2. Some coupon codes are only good for one registrant. With these codes, make sure that you are only registering one person on a single transaction.
3. If you purchased a Groupon deal, you will need to redeem your Groupon, revealing the coupon code.
If none of the above applies, then please contact the event directly for more information. You can contact them by filling out the Questions form found on the Event Page under Event Contact Info. Include the exact coupon code you tried to use.