b1.uberns.net has no CNAME records.
Question and response
Question
dig b1.uberns.net. NS
Answer
The response has no answer records.
Authority
uberns.net. 4796 SOA a1.uberns.net. itmanager.uberns.com. 2509110000 14400 7200 1209600 14400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0