Interesting. Following this page link it's marked as removed by the user, but it plays fine. The link without the https is youtu.be/zfBQHyuPXGg Try that.
As a test, I'll create a fresh link on this post to the same video.
Hmm, seems happy. If you mouse over the yellow box in the preceding post where the video URL is shown, your nav status will show a different URL. Might be a board hiccup. So clicking the prior post's video was sending you off into never-never land.