uk04.rocketseed.com has no CNAME records.
Question and response
Question
dig uk04.rocketseed.com. NS
Answer
The response has no answer records.
Authority
rocketseed.com. 600 SOA pdns05.domaincontrol.com. dns.jomax.net. 2026022301 28800 7200 604800 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0