Starting in autumn 2019, new payment regulations are coming into effect in EU countries when using EU cards to purchase from EU merchants.
This will add an additional security/authorization step to the payment process. The exact shape of this additional step is dependent on your bank or credit card company.
Although some countries already announced to delay those measures, Walls.io is already prepared for the new regulations, namely PSD2 and SCA ("strong customer authentication"). Our payment partner FastSpring rolled out support for those measures already.
This article from FastSpring has all the details available. The additional security step will just be a normal part of the purchase process that you will be guided through.
Please don't hesitate to contact our support team with any question about your payment.