Thank you so much for identifying this behavior. We have diagnosed the problem and updated the code to address this issue. Now, whenever the Robust Links API cannot resolve the domain of the submitted URI (e.g.,
https://www.bbc.co.uk/) to a global registered domain name (e.g.,
bbc.co.uk), it will return a 403. This change helps us address cases for localhost and 127.0.0.1 as well as other "private" or "local" host names (e.g.,
http://nightshade:8080/index.html or
http://192.168.1.1:5000/dir/index.php) that likely cannot be preserved in a public web archive.
Again, I really appreciate you bringing this to our attention.