crcvmail.navercorp.com has no CNAME records.
Question and response
Question
dig crcvmail.navercorp.com. NS
Answer
The response has no answer records.
Authority
navercorp.com. 180 SOA ns1.naver.com. webmaster.navercorp.com. 2026030604 21600 1800 1209600 180
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0