163mx02.mxmail.netease.com has no CNAME records.
Question and response
Question
dig 163mx02.mxmail.netease.com. NS
Answer
The response has no answer records.
Authority
mxmail.netease.com. 600 SOA ns-split3.netease.com. admin.nease.net. 1727 600 300 3600 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0