Webflow subscription products

I have added a subscription products to the apps.
But when going to buy it, an error appears in the .io URL(Screenshot by Lightshot). But the same error is not coming in the .com URL. But I want to test whether a product can be patched correctly.

Here is my site Read-Only: [LINK](Webflow - Natty Nurses)
(how to share your site Read-Only link)