archive.is returns A records 1.1.1.1 and 1.0.0.1 (cloudflare ips) back when you query them using cf dns. This means that your browser sends a request to 1.1.1.1 with the host header set to "archive.md". cloudflare's proxy tries to find the relevant config for archive.md, and not hosting it, tells you it doesn't host that page. it also helpfully informs you that if you just added your site to cloudflare, it might take a minute for it to show up.