If you see this message, there are a few things that might have happened. 

Could you be applying a gift voucher code to the offer code box ? There is a separate box for you to enter a gift voucher in - you may need to scroll down to see it, depending on what device you're using. 

Could you have entered the code slightly incorrectly? Zeros and letter O can look similar, and any additional spaces may prevent the code from working, so please double-check. 

If you know the code is correct and in date, please use the 'not helpful' button below, and you will be able to message us, so we can help you.