YouTube has changed how you embed videos. Don't ask me why the companies keep changing things that work. So, I have changed how you do it here.

Below the YT video, click Share.

Take the video code from the url or Share description. It will look something like oNk6-0rDdto. Insert it in place of xxxxxxxx below:

PHP Code:
[yt2]xxxxxxxxxx[/yt2
That will embed the video inside the post.