mx.energiedocs.com has no CNAME records.
Question and response
Question
dig mx.energiedocs.com. NS
Answer
The response has no answer records.
Authority
energiedocs.com. 2273 SOA dns.energiedocs.com. hostmaster.energiedocs.com. 1339810463 43200 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0