ip2-mx.iplannetworks.net has no MX records.
Question and response
Question
dig ip2-mx.iplannetworks.net. MX
Answer
The response has no answer records.
Authority
iplannetworks.net. 3600 SOA dns1.iplanisp.com.ar. hostmaster.iplan.com.ar. 2018122806 3600 600 1400000 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0