backupmx.dnsracks.net has no CNAME records.
Question and response
Question
dig backupmx.dnsracks.net. NS
Answer
The response has no answer records.
Authority
dnsracks.net. 5372 SOA ns3.wiplon.com. hostmaster.dnsracks.net. 2023101301 3600 900 604800 14400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0