Apex domains cannot have CNAME records.
Question and response
Question
dig weight-loss-ebook.com. NS
Answer
weight-loss-ebook.com. 5 NS ns-1378.awsdns-44.org.
weight-loss-ebook.com. 5 NS ns-1526.awsdns-62.org.
weight-loss-ebook.com. 5 NS ns-1564.awsdns-03.co.uk.
weight-loss-ebook.com. 5 NS ns-428.awsdns-53.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0