o7.mail.kashflow.com has no CNAME records.
Question and response
Question
dig o7.mail.kashflow.com. NS
Answer
The response has no answer records.
Authority
kashflow.com. 1800 SOA carl.ns.cloudflare.com. dns.cloudflare.com. 2394092370 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0