mail.mx.smartmail.com.ar has no MX records.
Question and response
Question
dig mail.mx.smartmail.com.ar. MX
Answer
The response has no answer records.
Authority
mx.smartmail.com.ar. 3600 SOA ns1.allytech.com. root.mx.smartmail.com.ar. 2024112507 7200 7200 2419200 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0