So I'm trying to embed a youtube video in a blog & using youtube's embedding codeL

<iframe width="560" height="315" src="https://www.youtube.com/embed/HZg1KaWwIfs" frameborder="0" allowfullscreen></iframe>

And it's not populating the video feed, only shows that embed code?

What am I doing wrong?

Only

https://youtu.be/HZg1KaWwIfs

 

Ok great, thank you. now how do I adjust the size of the video within the blog?  Not seeing any resizing arrows when clicking on it?

I do not use blog. But I think help you System/Settings - Posting/General -> Maximum video width