Adding a YouTube video doesn't work

Hey!
In the description editor I can select to add a video. Okay, adding a Vimeo URL works as expected. After publishing the changes, the video is being presented in the description.

Unfortunately, this is not the case for YouTube videos. Adding such an URL and publishing my changes, the video does not appear. It’s just missing.

Any suggestions?

Oh, just after posting this I came across this answer in another thread:

And this solved my problem. I always used the function of the editor instead of just pasting the URL.

Anyways… I really wish I could use plain Markdown here!

I recently uploaded a video to YT and then posted the link in the forum. People commented on it so I’m assuming it worked. I did it that way because (if I remember correctly) the forum wouldn’t let me load it directly.