smtp.customcall.us has no NS records.
NS records for this zone are defined at customcall.us.
NS records for this zone are defined at customcall.us.
Question and response
Question
dig smtp.customcall.us. NS
Answer
The response has no answer records.
Authority
customcall.us. 86400 SOA pdns99.ultradns.com. rob\.whritenour.enghouse.com. 2015062154 86400 86400 86400 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0