mail.goinet.com has no CNAME records.
Question and response
Question
dig mail.goinet.com. NS
Answer
The response has no answer records.
Authority
goinet.com. 1654 SOA ns1.ashcom.net. postmaster.ashcom.net. 2025091801 3600 1800 1800000 7200
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0