backup.mx.spoje.net has no NS records.
NS records for this zone are defined at mx.spoje.net.
NS records for this zone are defined at mx.spoje.net.
Question and response
Question
dig backup.mx.spoje.net. NS
Answer
The response has no answer records.
Authority
mx.spoje.net. 1800 SOA ns.spoje.net. tech.spoje.net. 1772388161 1800 3600 604800 1800
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0