ns40.domaincontrol.com has no CNAME records.
Question and response
Question
dig ns40.domaincontrol.com. NS
Answer
The response has no answer records.
Authority
domaincontrol.com. 405 SOA ans01.domaincontrol.com. dns.jomax.net. 2026021679 3600 7200 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0