Issue with blog page

I’m just building up my website and would it like to include a BLOG page, which I have already set up. The problem is that the posts don’t show up there (or anywhere). The issue is with the theme I’m guessing since if I switch to a different theme, they do show up in the BLOG page. Does anyone have any idea on how to fix this?

I’ve already set this:
Settings -> Reading -> Posts page: Blog