Apex domains cannot have CNAME records.
Question and response
Question
dig kakaoenterprise.com. NS
Answer
kakaoenterprise.com. 1 NS ns-1.awsdns-00.com.
kakaoenterprise.com. 1 NS ns-890.awsdns-47.net.
kakaoenterprise.com. 1 NS ns-1351.awsdns-40.org.
Authority
The response has no authority records.
Additional
ns-890.awsdns-47.net. 3 A 205.251.195.122
ns-1351.awsdns-40.org. 3 A 205.251.197.71
ns-1.awsdns-00.com. 3 AAAA 2600:9000:5300:100:0:0:0:1
ns-890.awsdns-47.net. 3 AAAA 2600:9000:5303:7a00:0:0:0:1
ns-1351.awsdns-40.org. 3 AAAA 2600:9000:5305:4700:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0