cisco.umbrella.com has no CNAME records.
Question and response
Question
dig cisco.umbrella.com. NS
Answer
The response has no answer records.
Authority
umbrella.com. 10378 SOA auth1.opendns.com. hostmaster.opendns.com. 1772570149 16384 2048 1048576 2560
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0