relay4.explore-blue.com has no CNAME records.
Question and response
Question
dig relay4.explore-blue.com. NS
Answer
The response has no answer records.
Authority
explore-blue.com. 3021 SOA NS53.DOMAINCONTROL.com. dns.jomax.net. 2026021902 28800 7200 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0