o4.ptr1750.email.signaturit.com has no MX records.
Question and response
Question
dig o4.ptr1750.email.signaturit.com. MX
Answer
The response has no answer records.
Authority
signaturit.com. 1800 SOA adam.ns.cloudflare.com. dns.cloudflare.com. 2398394504 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0