Display WordPress Posts not working?

I am not sure which version of wordpress I am currently using because I am just running a free blog. I am using the theme Sela, and I am trying to get an excerpt from my most recent blog post to display on the front page, as well as its featured image so users can see what the blog is about before clicking on it.

I am trying to use the “Display Blog Posts” widget which says that it “Displays a list of recent posts from another WordPress.com or Jetpack-enabled blog.” and gives me the option to enter the blog url, how many posts I want to display, etc. When I fill out the information and save, the only thing that displays is “We cannot load blog data at this time.”

My question is, does this widget not work when you are using the free version? Or am I just entering my information wrong?

Here is the link to the site:
https://atlanticwg.wordpress.com/