Apex domains cannot have CNAME records.
Question and response
Question
dig cloudappgurus.com. NS
Answer
cloudappgurus.com. 4 NS ns-299.awsdns-37.com.
cloudappgurus.com. 4 NS ns-1199.awsdns-21.org.
cloudappgurus.com. 4 NS ns-740.awsdns-28.net.
cloudappgurus.com. 4 NS ns-1872.awsdns-42.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0