dnsb.a1.hr has no CNAME records.
Question and response
Question
dig dnsb.a1.hr. NS
Answer
The response has no answer records.
Authority
a1.hr. 3312 SOA dnsa.a1.hr. dnsadmin.a1.hr. 2026030202 14400 3600 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0