To start, are you trying to enter it in the right place? See "Where do I fill in my promo code?"
If you are in the right place, you may have mixed up the letter O with the number 0.
There should be no spaces between the letters and numbers.
This code may have had a validity date, in which case you received an expiry date with the promo code by email.
This promotional code may require you to log in to your account, are you logged in? If not, see "I can't log in".
Once you have entered the coupon code correctly, press the enter key on your keyboard
If you have a business account, the promo code cannot be used. To use it, you must enter ‘Book for yourself’ when you log in.