What happens if 3-D Secure is not activated on the merchant's account?

If the issuer is applying new PSD2 ruleset and 3DS is not active in the merchant's account, the transaction will be rejected with a new error code - soft decline. Therefore, please make sure to have 3DS active for each brand in your account(s). If you are integrated with DirectLink (Server to Server), you will need to implement the soft decline mechanism.