Robots.txt problem

While building my website, I didn’t want anyone stumbling across a half-built site, so I selected an option through my theme’s settings > reading > search engines visibility > checked the box “Discourage search engines from indexing this site”.

Once I made a post, I wanted to test searching for it, so I unchecked that box and then googled the name of the post in quotes. The link shows up as the search result, but under the link it says “A description for this site is not available because of this site’s robots.txt” and when you click the link it takes you to an Error 404-Page NOT found” page.

I’ve done some searching on this forum and generally online about robots.txt, and what I’ve found is pretty much over my head. I’m unfortunately not a natural computer person (but I’m trying to learn!)

If someone knows how to fix this, could you please give me a simple explanation?

Thanks for any help!