mail.disesa.edu.do has no CNAME records.
Question and response
Question
dig mail.disesa.edu.do. NS
Answer
The response has no answer records.
Authority
disesa.edu.do. 10309 SOA ns70.dnns.net. it.dominet.net. 2026021501 3600 1800 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0