o2.email.vocaforce.com has no CNAME records.
Question and response
Question
dig o2.email.vocaforce.com. NS
Answer
The response has no answer records.
Authority
vocaforce.com. 3600 SOA ns53.domaincontrol.com. dns.jomax.net. 2025090401 28800 7200 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0