This error shows you, that the end-customer did not enter his 3DSecure password at the authentication page of the issuer:
1. One reason for this can be that the customer simply closed the authentication page and performed no action.
2. The second, most common reason (if there are many of these errors) is, that the customer is not properly redirected to the authentication URL returned from our system in the first response.
Be sure to redirect the customer to the provided URL and also add the returned post parameters to the redirect.