lost my blog at some point

I was showing my client the progress on my site and I discovered that my blog is no longer working.

If you click on any of these links the article is completely blank and I am not sure at what point I broke this functionality.

https://greatplainslandscapes.com/testpress/category/blog/

The files for the website are stored at:

https://github.com/shellwe/Great-Plains-Landscaping-WP

I am guessing it is something I did when tried to figure out how to utilize the_archive_title (which I believe I ultimately scrapped). I am hopeful it is just a quick fix for something I deleted accidentally and a pretty straight forward issue.