Apex domains cannot have CNAME records.
Question and response
Question
dig sas.com. NS
Answer
sas.com. 5 NS extdns03.na.sas.com.
sas.com. 5 NS extdns06.na.sas.com.
sas.com. 5 NS extdns01.na.sas.com.
sas.com. 5 NS extdns02.na.sas.com.
sas.com. 5 NS extdns05.na.sas.com.
sas.com. 5 NS extdns04.na.sas.com.
Authority
The response has no authority records.
Additional
extdns01.na.sas.com. 5 A 3.33.177.68
extdns02.na.sas.com. 5 A 40.120.32.101
extdns03.na.sas.com. 5 A 15.197.178.251
extdns04.na.sas.com. 5 A 3.33.177.68
extdns05.na.sas.com. 5 A 40.120.32.101
extdns06.na.sas.com. 5 A 15.197.178.251
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0