Youtube embed video code doesn't appear as video on blog post.

I have ever problem showing Youtube video on a blogger post once when I created a new blog. This is called embedding Youtube code. However, embedding code didn't seem to appear on new blog. The thing that puzzled me was that I could use the same method on my older blog to show the post, but it just didn't want to work on my new blog.

I get Youtube video embed code from Share button under the youtube video and then copy and paste the code on my Compose window. I really don't know why it works on my all of my old blogs, but just doesn't work on my newly created blog. I then saw "Edit HTML" tab, next to "Compose". I tried to post the code on "Edit HTML" window and it did work. Really weird, why embedding Youtube video code on new blog should be on the "Edit HTML" but on "Compose" just like the old blog can do. But never mind, at least I know how two methods on how to embed Youtube video codes.