Zero App with event date - post sorting

Hello Balbooa,
My website uses the zero app to post events. The Single Page Layout just has a Event Date field. The Category List Layout->Category list, uses sort by = Event Date.

However, currently, when the posts are displayed on the Category List Layout, they are shown oldest first (2025). I need the first post to be the most recent event (2026).

I'm sure the event posts used to display in the correct order. Can you please describe how I can reverse the sort order on the Event Date field.

Many thanks
Marc