No there is some new code in this forum software that recognizes that it is a youtube video automatically so it formats it to display.
On a regular website site html page you will need to use the share link url from youtube.

For example of your taylor switt video.
Visiting youtube the share selection shows for embed to use.

Code
<iframe width="560" height="315" src="https://www.youtube.com/embed/RsEZmictANA" frameborder="0" allow="accelerometer; autoplay; clipboard-write; encrypted-media; gyroscope; picture-in-picture" allowfullscreen></iframe>

So this is what it looks like with html enabled for this post which would be the same for your sites html pages.

Last edited by Ruben; 12/13/2020 4:43 PM.
There is no such thing as stupid questions , Just stupid answers.