Apex domains cannot have CNAME records.
Question and response
Question
dig t13as.com. NS
Answer
t13as.com. 5 NS ns-552.awsdns-05.net.
t13as.com. 5 NS ns-1219.awsdns-24.org.
t13as.com. 5 NS ns-1200.awsdns-22.org.
t13as.com. 5 NS ns-1512.awsdns-61.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0