70.128.49.38.customer.ientc.net.mx has no MX records.
Question and response
Question
dig 70.128.49.38.customer.ientc.net.mx. MX
Answer
The response has no answer records.
Authority
ientc.net.mx. 900 SOA ns-344.awsdns-43.com. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0