_spfB.docusign.com has no NS records.
NS records for this zone are defined at docusign.com.
NS records for this zone are defined at docusign.com.
Question and response
Question
dig _spfB.docusign.com. NS
Answer
The response has no answer records.
Authority
docusign.com. 300 SOA a1-246.akam.net. hostmaster.akamai.com. 2014102469 3600 1800 1209600 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0