mail1.polygen.com.pl has no MX records.
Question and response
Question
dig mail1.polygen.com.pl. MX
Answer
The response has no answer records.
Authority
polygen.com.pl. 60 SOA dns100.ovh.net. tech.ovh.net. 2026021800 86400 3600 3600000 60
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0