netadmin.isl.net.tw has no MX records.
Question and response
Question
dig netadmin.isl.net.tw. MX
Answer
The response has no answer records.
Authority
netadmin.isl.net.tw. 3600 SOA dns.isl.net.tw. root.isl.net.tw. 2002010802 7200 3600 604800 43200
Additional
. 0 OPT ; payload 1432, xrcode 0, version 0, flags 0