mail.ufinet.com.sv has no CNAME records.
Question and response
Question
dig mail.ufinet.com.sv. NS
Answer
The response has no answer records.
Authority
ufinet.com.sv. 1934 SOA ns1.ufinetlatam.net. noclatam.ufinetlatam.net. 2023011901 28800 7200 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0