smtp1.thains.co.th has no MX records.
Question and response
Question
dig smtp1.thains.co.th. MX
Answer
The response has no answer records.
Authority
thains.co.th. 1800 SOA ns1.thains.co.th. registry.thains.co.th. 2026022601 900 900 864000 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0