dns.icpnet.pl has no MX records.
Question and response
Question
dig dns.icpnet.pl. MX
Answer
The response has no answer records.
Authority
icpnet.pl. 3600 SOA dns.icpnet.pl. root.icpnet.pl. 2022110202 3600 180 86400 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0