mail.santana.com.py has no CNAME records.
Question and response
Question
dig mail.santana.com.py. NS
Answer
The response has no answer records.
Authority
com.py. 535 SOA a.dns.py. abuse.dns.py. 1771713007 1800 300 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0