bucks-smtp13.binarywizard.info has no MX records.
Question and response
Question
dig bucks-smtp13.binarywizard.info. MX
Answer
The response has no answer records.
Authority
binarywizard.info. 1800 SOA apollo.ns.cloudflare.com. dns.cloudflare.com. 2396108104 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0