mail3.us.scanscope.net has no CNAME records.
Question and response
Question
dig mail3.us.scanscope.net. NS
Answer
The response has no answer records.
Authority
scanscope.net. 900 SOA ns-1143.awsdns-14.org. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0