mail.uncu.edu.ar has no CNAME records.
Question and response
Question
dig mail.uncu.edu.ar. NS
Answer
The response has no answer records.
Authority
uncu.edu.ar. 431 SOA raiz.uncu.edu.ar. hostmaster.uncu.edu.ar. 2026030301 600 600 600 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0