On one page only - About us - it shows the page as I built it on the builder plug in but it doesn’t show me the editor box in the top right corner. All of the other pages work fine. I was in the process of loading a video at the bottom when it quit.
I have no issue embedding that video on my test site. You do have a JS error on your page that appears to be related to a slider from your theme (athena_slider). Did you add a slider to that page?
It looks like the problem here is how you added the code. The iframe code above works fine. But I believe you missed the closing </iframe> tag when you added it to that page, causing the rest of the code to be inside the iframe, rendering them useless. Take a look at the screenshot below for reference. Notice how all of the HTML elements after the iframe turned to black, instead of being color coded.