Apex domains cannot have CNAME records.
Question and response
Question
dig bookwithnuyu.com. NS
Answer
bookwithnuyu.com. 5 NS ns-1727.awsdns-23.co.uk.
bookwithnuyu.com. 5 NS ns-1504.awsdns-60.org.
bookwithnuyu.com. 5 NS ns-954.awsdns-55.net.
bookwithnuyu.com. 5 NS ns-1835.awsdns-37.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0