Single Video results empty – no errors

Any idea why Single Videos don’t work on my site, while galleries pulling from the playlist do? This happens whether I use the shortcode or the AYG block.

I don’t get any kind of error from YouTube.

It seems to load content for the modal popup, but it doesn’t load the content with the thumbnail and the link to trigger the popup. I just have this:

<!-- Gallery -->
    <div class="ayg-gallery ayg-row">
            </div>

Thanks in advance for any ideas.

The page I need help with: [log in to see the link]