ns2.flowmailer.net has no CNAME records.
Question and response
Question
dig ns2.flowmailer.net. NS
Answer
The response has no answer records.
Authority
flowmailer.net. 300 SOA ns1.flowmailer.net. contact.flowmailer.net. 2026022601 3600 300 7200 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0