Why does Teams show the <title> but not other meta tags when a page requires authentication?

Hi there,

I'm writing a HTML meta tag for displaying more info when pasting the link to the HTML in the chat, which falls under the category of basic meta data (https://learn.microsoft.com/en-us/microsoftteams/platform/messaging-extensions/how-to/link-unfurling?tabs=desktop%2Cjson%2Cadvantages).

It looks something like this  

<meta property="og:description" content="A concise description to appear in Teams preview." />

However, the HTML page is in the corporate server that requires authentication (e.g. corporate login).

When I copy the link from Microsoft Edge and paste the link in the chat, I notice that:

1. The link is transformed to the content of `<title>` of the HTML page
2. The description of specified by the meta tag is not showing

and I'm  wondering why is that?

For example, does it rely on my local browser to send a request (which should be able to fetch the meta tag)? or does it use Microsoft server to crawl the webpage  (which should not be able to fetch the meta tag)? Is there any documentation or material that explain how Teams handle this issue?

As for question 1, I believe it is because when copying a link from Microsoft Edge, it added extra information of the link, so that Teams has the ability to get the title instead of retrieving it from a HTTP request. Otherwise, it should be able to fetch the meta tag as well.

Thank you for the help