Apex domains cannot have CNAME records.
Question and response
Question
dig nordictugcharters.com. NS
Answer
nordictugcharters.com. 5 NS ns-1540.awsdns-00.co.uk.
nordictugcharters.com. 5 NS ns-680.awsdns-21.net.
nordictugcharters.com. 5 NS ns-14.awsdns-01.com.
nordictugcharters.com. 5 NS ns-513.awsdns-00.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0