Check that you have typed it in correctly. Promo codes are not case sensitive.
Alternatively, keep in mind that different promo codes are sent across to different users and markets, which is totally dependent on the promotions. In this case, that particular promo code will not work on your account.
General promo codes are sent to all users and are posted on our social media pages.
Some promo codes also have a maximum capacity of usage, once it is reached, the promo code will not work when added.