mx.stable.sk has no NS records.
NS records for this zone are defined at stable.sk.
NS records for this zone are defined at stable.sk.
Question and response
Question
dig mx.stable.sk. NS
Answer
The response has no answer records.
Authority
stable.sk. 10800 SOA ns.stable.cz. hostmaster.stable.cz. 2026012504 28800 7200 604800 10800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0