mail.em7service.cz has no NS records.
NS records for this zone are defined at em7service.cz.
NS records for this zone are defined at em7service.cz.
Question and response
Question
dig mail.em7service.cz. NS
Answer
The response has no answer records.
Authority
em7service.cz. 1800 SOA ns1.zcom.cz. hostmaster.zcom.cz. 1774031561 10800 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0