mail.lzsnet.com.ar has no MX records.
Question and response
Question
dig mail.lzsnet.com.ar. MX
Answer
The response has no answer records.
Authority
lzsnet.com.ar. 10800 SOA ns1.lzsnet.com.ar. postmaster.lzsnet.com.ar. 2010020806 28800 1800 2419200 10800
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0