office.ptera.com has no CNAME records.
Question and response
Question
dig office.ptera.com. NS
Answer
The response has no answer records.
Authority
ptera.com. 1502 SOA brady.ns.cloudflare.com. dns.cloudflare.com. 2396028327 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0