_spf.mailing-lists.it has no MX records.
Question and response
Question
dig _spf.mailing-lists.it. MX
Answer
The response has no answer records.
Authority
mailing-lists.it. 86400 SOA ns.kpnqwest.it. hostmaster.ns.kpnqwest.it. 2026021500 86400 7200 604800 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0