Embedded YouTube video not showing in web pages

Hi,

The following HTML code adds a YouTube video to the overview page of a challenge. On the original V1 challenge, or also by just opening the HTML file in a browser, it works.

<p style="text-align: center;"><iframe src="https://www.youtube.com/embed/kCe09Ic9vjE" frameborder="0" width="560" height="315"></iframe></p>

However, once uploaded on Codalab V2, the video isn't displayed.

V1:

V2: