So, that can be caused by so couple different things unless you share the link to your order form with me, I'll just make some assumptions here.
- The most usual case, is that you forgot to add any/some products to funnelish app under your funnel step! have you added those products there?
- The product(s) have missing/malformed properties, such as: Price, Payment Plan or Name.
Other than that I haven't personally encountered any case where that happens!
Let me know how it goes, will be glad to help!