mail.tango.hr has no CNAME records.
Question and response
Question
dig mail.tango.hr. NS
Answer
The response has no answer records.
Authority
tango.hr. 5486 SOA dns1.cdn.hr. root.avalon.hr. 2026010201 3600 1800 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0