mail3.mapfrebhd.com.do has no MX records.
Question and response
Question
dig mail3.mapfrebhd.com.do. MX
Answer
The response has no answer records.
Authority
mapfrebhd.com.do. 60 SOA gns1.mapfrebhd.com.do. hostmaster.mapfrebhd.com.do. 1335 900 600 86400 60
Additional
. 0 OPT ; payload 4000, xrcode 0, version 0, flags 0