Apex domains cannot have CNAME records.
Question and response
Question
dig intergas2015.com. NS
Answer
intergas2015.com. 2 NS ns-1324.awsdns-37.org.
intergas2015.com. 2 NS ns-1620.awsdns-10.co.uk.
intergas2015.com. 2 NS ns-814.awsdns-37.net.
intergas2015.com. 2 NS ns-1482.awsdns-57.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0