smtp.comnet.net.id has no CNAME records.
Question and response
Question
dig smtp.comnet.net.id. NS
Answer
The response has no answer records.
Authority
comnet.net.id. 1887 SOA ns1.comnet.net.id. hostmaster.comnet.net.id. 2024101601 43200 21600 2419200 43200
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0