wordpress preview box link not appearing

Sorry if I’m asking this question in the wrong place. I don’t even know what terms to use.

[ Moved to Fixing WordPress ]

When you paste a URL of another page of a wordpress site directly into the body of your post, it transforms into a preview of that page. The featured image pops up and the title and the first few lines. It appears in a box and the whole thing is a link.

This works for me most of the time, but sometimes, the URL does not transform. It just sits there and nothing happens. I cannot for the life of me figure out why. I do nothing different, but sometimes it works, sometimes it doesn’t. And it is driving me crazy because I can’t fix it after the fact. Once it decides not to work, it will never work.

Please help.

These two pages are supposed to be linked together. Scroll to the end and you’ll see the URLs:

https://longislandweekly.com/dear-evan-hansen-broadway-best/
https://longislandweekly.com/will-roland-brings-laughs-broadway-stage/

Here is an example of one that worked:

https://longislandweekly.com/cirque-du-soleil-soars-paramour/

Is there a name for this thing so at least I can search Google for help next time there’s a problem?