Apex domains cannot have CNAME records.
Question and response
Question
dig wyym168.com. NS
Answer
wyym168.com. 5 NS ns-577.awsdns-08.net.
wyym168.com. 5 NS ns-642.awsdns-16.net.
wyym168.com. 5 NS ns-1986.awsdns-56.co.uk.
wyym168.com. 5 NS ns-119.awsdns-14.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0