Who you using for DNS? iirc archive.today had a falling out with Cloudflare DNS because of a way they passed the requests onto archive.today so they stopped answering requests from Cloudflare DNS.
iirc, its not CF blocking the domain, its archive.today returning "bad" info when queries come from CF because disagree with the data CF give them.
For me, (I just checked) I get a valid ip for archive.today when I dig via CF however the server it returns is hosted in Hong Kong but a query via my ISP's DNS servers returns a server in the Netherlands.