postwall.ksc.net.th has no CNAME records.
Question and response
Question
dig postwall.ksc.net.th. NS
Answer
The response has no answer records.
Authority
ksc.net.th. 234 SOA ns.ksc.co.th. hostmaster.ns.ksc.co.th. 2025111800 3600 7200 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0