qemail.mktomail.com has no CNAME records.
Question and response
Question
dig qemail.mktomail.com. NS
Answer
The response has no answer records.
Authority
mktomail.com. 900 SOA ns1.marketo.com. ops.localhost. 2026012104 1800 1800 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0