mail.ib.systems has no MX records.
Question and response
Question
dig mail.ib.systems. MX
Answer
The response has no answer records.
Authority
ib.systems. 1800 SOA dara.ns.cloudflare.com. dns.cloudflare.com. 2397238077 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0