Apex domains cannot have CNAME records.
Question and response
Question
dig attask.com. NS
Answer
attask.com. 5 NS ns-662.awsdns-18.net.
attask.com. 5 NS ns-201.awsdns-25.com.
attask.com. 5 NS ns01.attask.com.
attask.com. 5 NS ns-1919.awsdns-47.co.uk.
attask.com. 5 NS ns-1886.awsdns-43.co.uk.
attask.com. 5 NS ns-316.awsdns-39.com.
attask.com. 5 NS ns02.attask.com.
attask.com. 5 NS ns-1461.awsdns-54.org.
attask.com. 5 NS ns-1495.awsdns-58.org.
attask.com. 5 NS ns-776.awsdns-33.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0