ns.umb.sk has no NS records.
NS records for this zone are defined at umb.sk.
NS records for this zone are defined at umb.sk.
Question and response
Question
dig ns.umb.sk. NS
Answer
The response has no answer records.
Authority
umb.sk. 1800 SOA nile.ns.cloudflare.com. dns.cloudflare.com. 2400146464 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0