mx.privatesystems.net has no CNAME records.
Question and response
Question
dig mx.privatesystems.net. NS
Answer
The response has no answer records.
Authority
privatesystems.net. 3451 SOA ns1.privatesystems.net. dns.privatesystems.net. 2026022601 3600 1800 1814400 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0