gblx.net.ar has no MX records.
Question and response
Question
dig gblx.net.ar. MX
Answer
The response has no answer records.
Authority
gblx.net.ar. 21600 SOA ns1.gblx.net.ar. hostmaster.impsat.net.ar. 2230202007 10800 3600 604800 21600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0