Apex domains cannot have CNAME records.
Question and response
Question
dig artgullsh.com. NS
Answer
artgullsh.com. 5 NS ns-1684.awsdns-18.co.uk.
artgullsh.com. 5 NS ns-1284.awsdns-32.org.
artgullsh.com. 5 NS ns-754.awsdns-30.net.
artgullsh.com. 5 NS ns-1607.awsdns-08.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0