Alt-rooted means that something other than the priced name system is in force.
As used here it means peering with the name servers here, which is automated like in letsencrypt as part of the SSO/user provisioning setup.
I make a reasonable commitment to make the following work if you can do on your own:
add the following name servers, which are non-recursive, to the top of your active resolver(s):
or their ip addresses if your resolver requires that.
- see en:Alt root