b.ns.bitnames.com has no CNAME records.
Question and response
Question
dig b.ns.bitnames.com. NS
Answer
The response has no answer records.
Authority
bitnames.com. 720 SOA ns1.us.bitnames.com. dnsoper.bitnames.com. 2026021003 7200 3600 3628800 7200
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0