mx.aonixiaoke.com has no CNAME records.
Question and response
Question
dig mx.aonixiaoke.com. NS
Answer
The response has no answer records.
Authority
aonixiaoke.com. 2264 SOA dns.aonixiaoke.com. hostmaster.aonixiaoke.com. 1665531168 43200 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0