monitor.he.net has no CNAME records.
Question and response
Question
dig monitor.he.net. NS
Answer
The response has no answer records.
Authority
he.net. 10260 SOA ns1.he.net. hostmaster.he.net. 202602210 10800 1800 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0