_spfb.exchange.accenture.com has no CNAME records.
Question and response
Question
dig _spfb.exchange.accenture.com. NS
Answer
The response has no answer records.
Authority
accenture.com. 900 SOA amrns1501.accenture.com. dnsadmin.accenture.com. 2029526194 10800 1080 604800 900
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0