mx3.etf.bg.AC.RS has no CNAME records.
Question and response
Question
dig mx3.etf.bg.AC.RS. NS
Answer
The response has no answer records.
Authority
etf.bg.ac.rs. 191 SOA NS1.NIC.RS. HOSTMASTER.ETF.RS. 2026020412 10800 3600 2419200 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0