esms.ksc.net has no MX records.
Question and response
Question
dig esms.ksc.net. MX
Answer
The response has no answer records.
Authority
ksc.net. 900 SOA ns2.ksc.net. admin.ns.ksc.co.th. 2021212426 7200 600 2419200 900
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0