Site Blocked via xfinity - but not via cellular

Hi all -

My family is trying to access content from their school (for distance learning).  That content works fine, except for videos that are embedded in the materials.  The videos are part of a service provided by loom.com.  Regardless of the device (iOS, ChromeOS, Windows with various browsers, etc.)  - the videos do not load when connected to my xfinity gateway. 

The videos do load if I connect via hotspot on my cell phone.   

So - it seems that xfinity is blocking this site somehow.  Firewall is currently set to "low" - and there aren't restrictions there.  Any suggestions for how to enable this content to make it's way through xfinity to my equipment? Settings to check, etc.?

Eric