The embedded code is not working when I put it on its own line in either the content space OR the HTML coding page. What is going on? When I enter it in the HTML coding page and hit "apply" it disappears and when I put it into the Content body it just shows it as text. Here is the YouTube link: 

<iframe width="560" height="315" src="http://www.youtube.com/embed/T4oTIJ-4mlE?rel=0" frameborder="0" allowfullscreen></iframe>

Please help. Thank you.