server.es3.in has no MX records.
Question and response
Question
dig server.es3.in. MX
Answer
The response has no answer records.
Authority
es3.in. 1800 SOA greg.ns.cloudflare.com. dns.cloudflare.com. 2395043215 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0