mx.gcmta.id has no CNAME records.
Question and response
Question
dig mx.gcmta.id. NS
Answer
The response has no answer records.
Authority
gcmta.id. 3332 SOA dns1.registrar-servers.com. hostmaster.registrar-servers.com. 1771507487 43200 3600 604800 3601
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0