ucps.uns.ac.rs has no MX records.
Question and response
Question
dig www.dmi.pmf.uns.ac.rs. MX
Answer
The response has no answer records.
Authority
dmi.pmf.uns.ac.rs. 3600 SOA dmi.pmf.uns.ac.rs. hostmaster.dmi.pmf.uns.ac.rs. 2020111804 10800 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0