mail.jtm2m.com has no CNAME records.
Question and response
Question
dig mail.jtm2m.com. NS
Answer
The response has no answer records.
Authority
jtm2m.com. 271 SOA ns1.iot247.net. hostmaster.iot247.net. 2024080502 10800 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0