Posts aren't showing on Single Post Page

I'm working on, and I created the theme with Builder.

When I try to view an individual post, the post content area is blank. From the backend, everything looks fine...

...except when I try to modify the single page template, the content says "post," and changing the settings for single page also changes the settings for single post, and vice versa.

Any suggestions? I have enabled support access through the parent site.