sg.gblnet.net has no MX records.
Question and response
Question
dig sg.gblnet.net. MX
Answer
The response has no answer records.
Authority
sg.gblnet.net. 3600 SOA ns.gblnet.net. vvv.gblnet.net. 2025100701 60 1200 12009600 259200
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0