WordPress Preview Not Working

I don't like Google as a company, but there's a reason I wind up using their search engine rather than DuckDuckGo. Here's an example.

I'm having a problem with WordPress where, if I hit "preview," I get an error page instead of a preview of my page (saying "This is somewhat embarrassing, isn’t it?"). In search of a solution, I go to DuckDuckGo and search for "WordPress preview page not found."

The result — a bunch of completely unhelpful pages.

Yeah, I know how to use the preview function, DuckDuckGo. How about help finding the problem I described in my search query? So, I go to Google with the exact same search term. Guess what?

Hey! There we go! Several sites with people posting about the problem I'm having. Maybe those sites will be useless, but at least I'm finding what I actually searched for. This site is the one that had the correct solution, by the way. Just in case the page disappears someday (which happens often), I'll recap the steps to fix this problem below.

1. In your browser, log out of your WordPress site (or sites if you have more than one logged in.)
2. Close all your browser windows, even the minimized ones.
3. Relaunch your browser and make sure it only has only one tab open.
4. Click the menu at the top right of your browser window (it usually three horizontal lines)  and choose "Settings." This opens up a new page.
5. Click on the "History" tab at the top. Then click "clear browsing data" on the left hand side.
6. Under "advanced," check everything except passwords and auto-fill form data. Then click "clear data."
7. Repeat the process under Basic, with browsing history, cookies, and caches images and files. Choose "all time" for the time range and choose "clear data."
8. Close your browser and start it up again.