test.tsc.co.th has no CNAME records.
Question and response
Question
dig test.tsc.co.th. NS
Answer
The response has no answer records.
Authority
tsc.co.th. 8125 SOA ns2.ksc.net. hostmaster.ns.ksc.co.th. 2015022808 28800 7200 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0