The card issuers' Access Control Server (ACS) are responsible for rendering the step-up (challenge) authentication page before redirecting the customer back to the Term URL to complete the authentication.
In rare cases, the ACS page can fail to render correctly before or after the customer is prompted to verify their identity.
If a blank page from the ACS is displayed to the customer during 3D-Secure step-up authentication, this can happen for a number of reasons. In most cases this is due to:
- Latency on the ACS
- ISP latency in the card issuers' location
- ISP latency for the customer
Latency issues will normally result in an incomplete challenge, which is displayed in MyST as a THREEDQUERY with enrolled “Y” and status “C” for EMV 3DS version 2 (or a blank status for 3-D Secure version 1), with no related AUTH requests shown.
The authentication page is hosted on the card issuers' ACS, meaning Trust Payments cannot be notified of a problem, as this has occurred on a third party server. Because problems such as these are temporary in nature, asking your customers to retry the transaction at a different time or from a different device can often resolve the issues.
Another common problem is when the payment checkout is loaded in an iframe that has been configured with attribute sandbox. This attribute enables an extra set of restrictions for the content of the iframe. Failing to specify any specific sandbox restrictions will cause all restrictions to be applied, which will block the form from being submitting on the ACS. If customers are reporting that they are experiencing a blank ACS page, please review your integration and first confirm whether or not you have any restrictions applied to the iframe element.
If the blank ACS issue persists for a specific customer, this could indicate an issue with the card issuer's ACS and in this situation we would recommend contacting our Support Team to raise this with the relevant card issuer, providing as much information as possible.