mail2.dotarai.co.th has no CNAME records.
Question and response
Question
dig mail2.dotarai.co.th. NS
Answer
The response has no answer records.
Authority
dotarai.co.th. 1591 SOA ns.mail.in.th. hostmaster\.mail.in.th. 2026022623 86400 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0