mxbackup.pacificinternet.com has no CNAME records.
Question and response
Question
dig mxbackup.pacificinternet.com. NS
Answer
The response has no answer records.
Authority
pacificinternet.com. 22 SOA dns1.pacificinternet.com. noc.pacificinternet.com. 2025121600 7200 1800 1209600 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0