Blog Posts don’t open in single page

I’m working on a site at https://www.makeashift.org. If you click on a blog post title or “read more” tag, it should take the post to its own page, but I get an error stating “sorry, what you are looking for isn’t here”.

Any thoughts on what the problem might be? By the way, my blog is set up to be a secondary page, and not the home page. thanks for your help.