Comment by Thorrez

    dig @carl.archive.is archive.is A +noedns

responds 134.119.220.26

    curl http://134.119.220.26 -H 'Host: archive.is' -v

responds with HTML of the site.

I'm not a dig expert, but I believe this means it works without EDNS. I think that means archive.is is specifically blocking Cloudflare's servers, not blocking all non-EDNS requests.