mail.panelplus.pl has no MX records.
Question and response
Question
dig mail.panelplus.pl. MX
Answer
The response has no answer records.
Authority
panelplus.pl. 10800 SOA dns2.panelplus.pl. admin.infoplus.com.pl. 2026012701 3600 3600 604800 10800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0