It responds fine for me but I am using my own DNS server that talk directly to the root/tld servers.
Here are some other public DNS servers. [1] ...not my site
Alternatively use 107.189.8.227 in your hosts file for each of those names for now though it does change.
DNS resolution is not the issue. Like you, I use my own recursive resolver and the various archive.[today|il|is|ph|etc] sites all resolve without issue, but weirdly MXToolbox[0] resolves those hosts to a different IP address.
I suppose my ISP could be intercepting my recursive queries, but that seems unlikely as I've never detected a dns proxy before.
I'll do some more investigating and, if it is my ISP, I've been looking for a reason to dump them anyway.
Edit: I just noticed that the Tor browser indicates a .onion version of the website is available and it works perfectly.