imbed frame on a website

I have a frame on the website available to my students that would allow them to solve the daily puzzle, but it is no longer presenting.  The frame is now just a plain white box.  I am not sure how to fix this at this point.  I did see a posting on another forum, but no responses.  I had read how to do this on the support portion of the site at one point, but can no longer find it.

My students are in a VERY restricted environment and I can only allow certain websites because of that.  If anyone has an idea...
I had sent in a help desk ticket, but got a reply to post here.

Are you using the Public API to get the URL of the puzzle to embed?

This is what the original article gave me to use:
<iframe style="width: 400px; height: 560px;" src="https://www.chess.com/daily_puzzle" frameborder="0"></iframe>

That loads via browser correctly so theoretically should also work.

This club is specifically about the Public API so doesn't really impact that.

There is a change with how the daily puzzle links, that might be related; I'll ask if that embed might be impacting you.