mxbh.socketlabs.com has no NS records.
NS records for this zone are defined at socketlabs.com.
NS records for this zone are defined at socketlabs.com.
Question and response
Question
dig mxbh.socketlabs.com. NS
Answer
The response has no answer records.
Authority
socketlabs.com. 900 SOA ns-929.awsdns-52.net. dnsadmin.socketlabs.com. 2017110200 7200 900 1209600 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0