ns31.suthost.com has no MX records.
Question and response
Question
dig ns31.suthost.com. MX
Answer
The response has no answer records.
Authority
suthost.com. 600 SOA ns7.alidns.com. hostmaster.hichina.com. 2026010913 3600 1200 86400 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0