Apex domains cannot have CNAME records.
Question and response
Question
dig ains.com. NS
Answer
ains.com. 5 NS ns-199.awsdns-24.com.
ains.com. 5 NS ns-1180.awsdns-19.org.
ains.com. 5 NS ns-854.awsdns-42.net.
ains.com. 5 NS ns-1678.awsdns-17.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0