dns4.hitme.net.pl has no MX records.
Question and response
Question
dig dns4.hitme.net.pl. MX
Answer
The response has no answer records.
Authority
dns4.hitme.net.pl. 3600 SOA dns1.rootvps.pl. admin.hitme.pl. 2019112123 28800 7200 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0