ns2.commonmx.com has no CNAME records.
Question and response
Question
dig ns2.commonmx.com. NS
Answer
The response has no answer records.
Authority
commonmx.com. 3147 SOA ns-usa.topdns.com. hostmaster.topdns.com. 2026020301 43200 900 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0