o7.ptr885.eventsairmail.com has no CNAME records.
Question and response
Question
dig o7.ptr885.eventsairmail.com. NS
Answer
The response has no answer records.
Authority
eventsairmail.com. 3374 SOA ns1.dnsimple.com. admin.dnsimple.com. 2014081491 86400 7200 604800 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0