ns3.itcsa.net has no MX records.
Question and response
Question
dig ns3.itcsa.net. MX
Answer
The response has no answer records.
Authority
itcsa.net. 3600 SOA choique.itcsa.net. admin.itcsa.net. 2006060746 3600 600 86400 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0