Apex domains cannot have CNAME records.
Question and response
Question
dig fullwebinfo.com. NS
Answer
fullwebinfo.com. 3 NS ns-883.awsdns-46.net.
fullwebinfo.com. 3 NS ns-756.awsdns-30.net.
fullwebinfo.com. 3 NS ns-531.awsdns-02.net.
fullwebinfo.com. 3 NS ns-700.awsdns-23.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0