edm.smartclick.co.th has no CNAME records.
Question and response
Question
dig edm.smartclick.co.th. NS
Answer
The response has no answer records.
Authority
smartclick.co.th. 10800 SOA ns6.smartclickonline.com. yod.yod.net. 2026022413 3600 1800 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0