ns3.onlinenow.com.ar has no MX records.
Question and response
Question
dig ns3.onlinenow.com.ar. MX
Answer
The response has no answer records.
Authority
onlinenow.com.ar. 86400 SOA ns5.onlinenow.com.ar. marcelopedraampm.gmail.com. 2026021301 3600 1800 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0