Solved: "sort" sometimes missing in "Collection List Settings"

In a Collection List I just created, there is no sorting option:
image

But in one created on a different page, sorting is available:

  1. How does such a difference arise?
  2. How do I enable sorting, where it is currently disabled?

Edit: I found the answer!

“Readers” is a field. I meant to pick a Collection, “Blog Post Readers”.


Read-only link: Webflow - InjAnnuity Main Site
Here is my public share link: https://injannuity-main-site.webflow.io/