mail.totisp.net has no NS records.
NS records for this zone are defined at totisp.net.
NS records for this zone are defined at totisp.net.
Question and response
Question
dig cisp-mta-01.totisp.net. NS
Answer
The response has no answer records.
Authority
totisp.net. 300 SOA ns1.totisp.net. admin.totisp.net. 2018112463 21600 7200 604800 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0