Problems with registration returning to the subscription page without allowing payment or subscripti

I have a membership site (a non-profit membership) that has a subscription for a year called "professional" with general access to items on the website and discount rates on Events.

I have other subscriptions, call it "X" that are listed as private so that they don't show up on the main registration page, but do show up on the subscription page with a short code [professional]. The idea is that I don't want an "X" subscription without already having a "Professional" membership.

However when someone clicks on the "X" subscription button, it takes the user right back to the subscription page without payment or enrolling.

Please advise.