Apex domains cannot have CNAME records.
Question and response
Question
dig tinasean2021.com. NS
Answer
tinasean2021.com. 5 NS ns-1127.awsdns-12.org.
tinasean2021.com. 5 NS ns-226.awsdns-28.com.
tinasean2021.com. 5 NS ns-318.awsdns-39.com.
tinasean2021.com. 5 NS ns-556.awsdns-05.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0