mail.mec.edu.do has no CNAME records.
Question and response
Question
dig mail.mec.edu.do. NS
Answer
The response has no answer records.
Authority
mec.edu.do. 10800 SOA ns1.site5.com. pedro.sosuanet.com. 2025082500 86400 7200 3600000 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0