mx01.windstream.net has no NS records.
NS records for this zone are defined at windstream.net.
NS records for this zone are defined at windstream.net.
Question and response
Question
dig mx01.windstream.net. NS
Answer
The response has no answer records.
Authority
windstream.net. 3600 SOA ns5-auth.windstream.net. hostmaster.windstream.net. 2020102757 28800 7200 3600000 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0