Why does the page redirected to checkout upon clicking the "Start Now" button in the module overview page?

Users that are not logged-in or registered will be redirected on the checkout page upon click of the "Start Now" button. Guest users will either sign in or register to proceed to the module lessons. Click the "Place Order" button to proceed. In the checkout confirmation page, click the title of the module to open the module overview page. In the module overview page, click the "Start Now" button to begin exploring the module.

Upon clicking a part of a lesson in the curriculum tab of the module overview page, the lessons page has a notification saying that the content is protected.

Contents are protected for those who are not able to login or register and haven't started the module.