dc3.bigmachines.com has no CNAME records.
Question and response
Question
dig dc3.bigmachines.com. NS
Answer
The response has no answer records.
Authority
bigmachines.com. 300 SOA ns1.p201.dns.oraclecloud.net. hostmaster.bigmachines.com. 2020129559 3600 600 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0