Why did the risk rule not get triggered on this transaction?

There can be several reasons why a certain risk rule did not trigger. Many risk rules require data that should be submitted in the payment request. For example, the Shopper IP address Velocity risk rule requires the merchant to submit the Shopper IP address.

Another reason could be related to the Payment Method as not all payments are applicable to a risk assessment. Most of the alternative payment methods are excluded for risk.

In case it is not clear after the review, you can send a request to Support to review the case. It is recommended to share the PSP reference.