lmr.edu.do has no MX records.
Question and response
Question
dig lmr.edu.do. MX
Answer
The response has no answer records.
Authority
lmr.edu.do. 7200 SOA dns4.midominio.do. r.rod.lumuri.edu.do. 2020020406 7200 7200 172800 38400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0