Apex domains cannot have CNAME records.
Question and response
Question
dig samsung.com. NS
Answer
samsung.com. 5 NS auth01.sam.ic.
samsung.com. 5 NS dnsst2.samsung.com.
samsung.com. 5 NS dns-gi2.samsung.com.
samsung.com. 5 NS dnssm2.samsung.com.
samsung.com. 5 NS dnssm.samsung.com.
samsung.com. 5 NS dnsst.samsung.com.
samsung.com. 5 NS dns-gi1.samsung.com.
samsung.com. 5 NS dns-awskr1.samsung.com.
Authority
The response has no authority records.
Additional
dnssm.samsung.com. 5 A 203.241.132.51
dnsst.samsung.com. 5 A 203.241.135.51
dnssm2.samsung.com. 5 A 112.107.53.58
dnsst2.samsung.com. 5 A 112.106.53.58
dns-gi1.samsung.com. 5 A 203.241.132.185
dns-awskr1.samsung.com. 5 A 52.79.211.80
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0