mail3.correonegocios.com has no MX records.
Question and response
Question
dig mail3.correonegocios.com. MX
Answer
The response has no answer records.
Authority
correonegocios.com. 900 SOA dns1.triara.com. hostmaster.triara.com. 2007051987 10800 3600 604800 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0