proxmox.s4r.it has no MX records.
Question and response
Question
dig proxmox.s4r.it. MX
Answer
The response has no answer records.
Authority
s4r.it. 14400 SOA ns1.th.seeweb.it. hostmaster.seeweb.it. 2025080800 86400 7200 2592000 14400
Additional
. 0 OPT ; payload 1680, xrcode 0, version 0, flags 0