NS3.METROTEL.AR has no MX records.
Question and response
Question
dig NS3.METROTEL.AR. MX
Answer
The response has no answer records.
Authority
metrotel.ar. 43200 SOA ns1.cps.com.ar. hostmaster.cps.com.ar. 2010084363 3600 900 86400 43200
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0