Link previews don't always appear

[ECollins]

Why do some Team Chat links not show the web page preview?
Windows,  Zoom 5.14.11

Example 1: This does show a preview.
https://nwwildflowers.com/places/?fbclid=IwAR1fibuLGPDV_jGQiexaQHdIzfNZvmC5D6wSBIJilphdObpl47i8ddAMd...

Example 2: This does *not* show a preview. 
http://www.drwdesignbuild.com/se-14th-avenue/remodel-exterior1