mail.captiontext.com has no NS records.
NS records for this zone are defined at captiontext.com.
NS records for this zone are defined at captiontext.com.
Question and response
Question
dig mail.captiontext.com. NS
Answer
The response has no answer records.
Authority
captiontext.com. 3600 SOA ns1.viawest.net. hostmaster.viawest.net. 7 43200 7200 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0