m300.mail.163.com has no MX records.
Question and response
Question
dig hdweb.mail.ntes53.netease.com. MX
Answer
The response has no answer records.
Authority
ntes53.netease.com. 60 SOA ns1-ntes53.netease.com. admin.nease.net. 20161703 600 300 3600 60
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0