esms.ksc.net has no CNAME records.
Question and response
Question
dig esms.ksc.net. NS
Answer
The response has no answer records.
Authority
ksc.net. 900 SOA ns1.ksc.net. admin.ns.ksc.co.th. 2021212631 7200 600 2419200 900
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0