App Navigation - Links show In Content Area

I am trying to create links inside a workspace app navigation. I added a documentation section and links to sharepoint pages built specifically for this purpose. If I add the link to show in a new tab ti display correctly. But if I select in Content Area then it displays a message warning this is not content provided by Microsoft and refused to connect.  I've tried the same idea to link to a Teams channel.

These are Microsoft products, so why does this not work embedding insde of its own applications?? Is there a way to whitelist sites to be able to show here? 

However, a link to a Guy in a Cube youtube video does work, Adam and Patrick must have pull 🙂

Any clarification or assistance is greatly appreciated.

Thanks

Thanks