We know it’s annoying but this can happen for a number of reasons. Some of our vouchers are available for a limited time - so you may be trying to use it after it’s expired.
Additionally you may have previously used the same code, or it does not apply to the items or price value in your basket.
You can also only use one voucher per order.
Please make sure you check the information on the voucher and in the terms and conditions.
If you are still struggling or believe the code you are trying to use is valid, then please get in contact with our Live Chat team.