mx.decknet.net has no NS records.
NS records for this zone are defined at decknet.net.
NS records for this zone are defined at decknet.net.
Question and response
Question
dig mx.decknet.net. NS
Answer
The response has no answer records.
Authority
decknet.net. 3600 SOA ns1.decknet.com. postmaster.decknet.fr. 2021072601 10800 3600 604800 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0