_spf.jazztel.es has no MX records.
Question and response
Question
dig _spf.jazztel.es. MX
Answer
The response has no answer records.
Authority
jazztel.es. 7200 SOA dns.jazztel.es. admin.jazztel.es. 2014061466 7200 7200 2419200 7200
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0