mx6.emailowl.com has no CNAME records.
Question and response
Question
dig mx6.emailowl.com. NS
Answer
The response has no answer records.
Authority
emailowl.com. 729 SOA lily.ns.cloudflare.com. dns.cloudflare.com. 2396499185 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0