dynamic.orange.es has no MX records.
Question and response
Question
dig dynamic.orange.es. MX
Answer
The response has no answer records.
Authority
dynamic.orange.es. 172800 SOA dns4.wanadoo.es. dnsmaster.es.orange-ftgroup.com. 2006061914 86400 7200 2592000 172800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0