Apex domains cannot have CNAME records.
Question and response
Question
dig 0-nail.com. NS
Answer
0-nail.com. 5 NS ns-748.awsdns-29.net.
0-nail.com. 5 NS ns-6.awsdns-00.com.
0-nail.com. 5 NS ns-347.awsdns-43.com.
0-nail.com. 5 NS ns-1776.awsdns-30.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0