Blog post was posted, but isn't showing up on the blog page or in backend

So I wrote a new post

http://mitrailleuse.net/2015/09/08/power-word-blackface/

It said “Congratulations, 38th post!” like normal. But it isn’t showing up on the blog’s page, in the “recent posts” or even in the backend of the blog. Why is that?

Notice how http://mitrailleuse.net/ doesn’t show it, even though it should show the newest post at the top, and this is the newest post.