erp-server.mirae.com has no MX records.
Question and response
Question
dig erp_server.mirae.com. MX
Answer
The response has no answer records.
Authority
mirae.com. 600 SOA mirae.com. root.mirae.com. 2017061401 3600 1200 864000 600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0