mail.cloudmonit.pl has no MX records.
Question and response
Question
dig mail.cloudmonit.pl. MX
Answer
The response has no answer records.
Authority
cloudmonit.pl. 600 SOA ns1.monit24.pl. dns.monit24.pl. 2022042001 28800 7200 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0