smtp.viva.net.do has no MX records.
Question and response
Question
dig smtp.viva.net.do. MX
Answer
The response has no answer records.
Authority
viva.net.do. 38400 SOA NS1.TRILOGY.NET.DO. rchavez.centennialrd.com. 2020090501 10800 3600 604800 38400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0