Like a growing number of providers, they ignore the rules about DNS. Try to access a page which doesn't exist in a browser and you get a redirect to an error page instead of a NXDOMAIN.
There is some quite clever stuff going on here, BUT MAKING THAT REDIRECT CACHEABLE IS NOT ONE OF THEM.
Particularly when your DNS forwarders are on the blink!
They don't even have the sense to return a 404 code!
Could they do any worse? Actually, yes, they could! The frame handling is just silly.
colin@animal ~ $ curl -i 'http://kshgauyuegvuaFRA.com/none.html' HTTP/1.1 200 OK Server: nginx Date: Thu, 20 Feb 2020 19:46:59 GMT Content-Type: text/html; charset=utf-8 Transfer-Encoding: chunked Connection: close Expires: Thu, 20 Feb 2020 19:56:59 GMT Cache-Control: max-age=600 X-Frame-Options: DENY
SWMBO thought we should report this to their support. Unfortunately the online chat people had all gone home early.
Which mean dealing with IVR-of-pain before eventually speaking to some poor helpdesk person in India who had trouble spelling DNS. They assured me that there was "nothing wrong with my line" despite me trying to tell them I knew that - the problem was with their DNS server and their web server.
They hung up on me.