Apex domains cannot have CNAME records.
Question and response
Question
dig fullsail.com. NS
Answer
fullsail.com. 1 NS ns-1876.awsdns-42.co.uk.
fullsail.com. 1 NS ns-71.awsdns-08.com.
fullsail.com. 1 NS ns-694.awsdns-22.net.
fullsail.com. 1 NS ns-1476.awsdns-56.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0