markets.books.microsoft

Unsafe website reported.

To be clear, you will have to go to the markets.books.microsoft.com site which means indicating to bitdefender that you understand the risks and still want to navigate to the site. when the site opens up you will find a message "request cannot be served" as the site no longer exists.

from there you will follow darrens instructions 

I actually checked both checkboxes

Great Idea Darren

I will do this

Since the expired certificate issue is still ongoing - I reported the site https://markets.books.microsoft.com as unsafe to Microsoft. Maybe if you all do the same, they might take notice!

In Edge go to the site, then go to Help and Feedback, just below Settings in Edge, then "Report an unsafe site", then tick one of boxes to indicate site is phishing or contains malware, and submit.

I also sent a report via the Feedback hub with a screenshot of the expired cert, hopefully that gets noticed also!

Books is no longer supported and as such MS obviously won't update the certificate

This doesn't stop other software from referencing that site (Doesn't need to be Microsoft even though you're using edge)

but since Books is no longer supported, Bitdefender is correct in blocking it (IT IS NO LONGER SUPPORTED)

Now Microsoft has no power to stop other software from referencing this outdated and unsupported site so stop blaming Microsoft.

A more useful question is "why doesn't Bitdefender highlight the app or origin of the request to access the books site" then you can see where the request is coming from.