@stanford @ernest As far as I know, lemmy.ml itself is not blocking kbin requests...
lemmy.ml is returning 403 forbidden responses at any of it's endpoints when the useragent string contains "kbinbot". We know this because we've tried all variations. Brave kbin instance admins willing to change their useragents are able to federate just fine with lemmy.ml.
This is not a Lemmy thing, its implemented at the server or firewall level. Lemmy.ml admins have not responded at all.