ns1.blue.net has no CNAME records.
Question and response
Question
dig ns1.blue.net. NS
Answer
The response has no answer records.
Authority
blue.net. 2425 SOA ns1.blue.net. adminblue.blue.net. 520800008 1200 180 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0