Apex domains cannot have CNAME records.
Question and response
Question
dig maingun.org. NS
Answer
maingun.org. 5 NS ns-562.awsdns-06.net.
maingun.org. 5 NS ns-1846.awsdns-38.co.uk.
maingun.org. 5 NS ns-242.awsdns-30.com.
maingun.org. 5 NS ns-1466.awsdns-55.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0