Apex domains cannot have CNAME records.
Question and response
Question
dig hersbak.com. NS
Answer
hersbak.com. 5 NS ns-1432.awsdns-51.org.
hersbak.com. 5 NS ns-2044.awsdns-63.co.uk.
hersbak.com. 5 NS ns-1045.awsdns-02.org.
hersbak.com. 5 NS ns-2014.awsdns-59.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0