server18.viwefix.cz has no CNAME records.
Question and response
Question
dig server18.viwefix.cz. NS
Answer
The response has no answer records.
Authority
viwefix.cz. 300 SOA dns.viwefix.cz. hostmaster.viwefix.cz. 2026021100 10801 3600 3600000 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0