dns2.smadm.pl has no MX records.
Question and response
Question
dig dns2.smadm.pl. MX
Answer
The response has no answer records.
Authority
smadm.pl. 600 SOA dns1.smadm.pl. dns2.smadm.pl. 2026020901 1800 600 1209600 14400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0