host15.co154.isl.net.tw has no MX records.
Question and response
Question
dig host15.co154.isl.net.tw. MX
Answer
The response has no answer records.
Authority
co154.isl.net.tw. 86400 SOA dns.isl.net.tw. root.isl.net.tw. 2002022202 43200 3600 604800 86400
Additional
. 0 OPT ; payload 1432, xrcode 0, version 0, flags 0