As stated in the doc here, I have created an API key with iframely and have also submitted that key in comethcat extensions for rich media preview in cometchat dashboard.
On posting any URL message in the chat box of widget, it is making a hit to the iframely service (have checked on their dashboard) but no response or meta data related to that extension(as mentioned in the doc response structure) is present in the final API response.
I am also using comet chat Link preview extension and meta data related to that is present in the final api response but nothing related to content for rich media preview
platform: cometchat javascript widget