mail.ergos.edu.do has no NS records.
NS records for this zone are defined at ergos.edu.do.
NS records for this zone are defined at ergos.edu.do.
Question and response
Question
dig mail.ergos.edu.do. NS
Answer
The response has no answer records.
Authority
ergos.edu.do. 120 SOA ns1.dynu.com. administrator.dynu.com. 66 3600 900 604800 300
Additional
. 0 OPT ; payload 1280, xrcode 0, version 0, flags 0