mx01.enter.it has no NS records.
NS records for this zone are defined at enter.it.
NS records for this zone are defined at enter.it.
Question and response
Question
dig mx01.enter.it. NS
Answer
The response has no answer records.
Authority
enter.it. 86400 SOA dante.enter.it. hostmaster.enter.it. 2020012302 86400 7200 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0