If I copy and paste a regular Amazon link (http://www.amazon.com/) into chat, the system will expand the link and create a preview of the product.
Many people, myself included, shop using Amazon Smile so that Amazon will donate part of our purchases to charities we select. In order for this to work, one must browse and purchase using a different subdomain (http://smile.amazon.com/).
If I am browsing Amazon Smile (my default) and copy and paste a link into chat, the system treats it like a regular link and not one of the few domains it recognizes and can create a preview.
Please update the Amazon preview to work with the "smile" subdomain as well as "www".