dns.prod.nic.as has no MX records.
Question and response
Question
dig dns.prod.nic.as. MX
Answer
dns.prod.nic.as. 5 CNAME srs.prod.nic.as.
Authority
nic.as. 10800 SOA ns-235.awsdns-29.com. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0