The most common cause is a simple mistake in letters or numbers. Therefore, our recommendation is to copy the code from the voucher email into the input field. Make sure not to enter any spaces in the voucher field.
It could also be that the voucher has already been redeemed. Alternatively, the validity period of your voucher may have already expired.
Please also pay attention to the conditions of the voucher, often certain brands or already reduced items are excluded or there may be a minimum order value required.