Learndash Payment Problem

We have Learndash installed on our website https://davincischool.net/courses/hello-geometry-pre-sale/ The payment portal seems to be set up correctly, for both paypay and stripe, however, when we press the enrol button the payment portal does not appear. Instead the user is directed to the home page. We have tested for plugin and theme conflicts but the problem persists.

We need someone to trouble shoot and fix this issue.