o2.ptr4218.gocadmium.com has no CNAME records.
Question and response
Question
dig o2.ptr4218.gocadmium.com. NS
Answer
The response has no answer records.
Authority
gocadmium.com. 1800 SOA elle.ns.cloudflare.com. dns.cloudflare.com. 2398296795 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0