mx.lexsynergy.com has no CNAME records.
Question and response
Question
dig mx.lexsynergy.com. NS
Answer
The response has no answer records.
Authority
lexsynergy.com. 412 SOA ns01.lexsynergy.com. dnsmaster.lexsynergy.com. 2011076284 86400 3600 1209600 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0