Apex domains cannot have CNAME records.
Question and response
Question
dig xinlutang168.com. NS
Answer
xinlutang168.com. 5 NS ns-1407.awsdns-47.org.
xinlutang168.com. 5 NS ns-1928.awsdns-49.co.uk.
xinlutang168.com. 5 NS ns-1061.awsdns-04.org.
xinlutang168.com. 5 NS ns-1591.awsdns-06.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0