mail.choruscall.com has no NS records.
NS records for this zone are defined at choruscall.com.
NS records for this zone are defined at choruscall.com.
Question and response
Question
dig mail.choruscall.com. NS
Answer
The response has no answer records.
Authority
choruscall.com. 900 SOA cbru.br.ns.els-gms.att.net. rm-hostmaster.ems.att.com. 405 3600 600 1209600 900
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0