coro.net.do has no MX records.
Question and response
Question
dig coro.net.do. MX
Answer
The response has no answer records.
Authority
coro.net.do. 1800 SOA elsa.ns.cloudflare.com. dns.cloudflare.com. 2395737950 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0