mail.bvacom.net has no CNAME records.
Question and response
Question
dig mail.bvacom.net. NS
Answer
The response has no answer records.
Authority
bvacom.net. 600 SOA ns0.bvacom.net. hostmaster.bvacom.net. 2015072900 86400 21600 3600000 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0