I am trying to embed one of our company instructional how to videos into a email template.

I click on the HTML tab

It lets me insert, I see a preview, I click save and the embed is removed.

Help please?

Below is the HTML

<iframe width="560" height="315" src="https://www.youtube.com/embed/s3EMWr3SNfA" frameborder="0" allowfullscreen></iframe>

Thank you