isp2.obslugasieci.pl has no MX records.
Question and response
Question
dig isp2.obslugasieci.pl. MX
Answer
The response has no answer records.
Authority
obslugasieci.pl. 28800 SOA dns1.obslugasieci.pl. pczerw.sieci.net.pl. 2025111001 28800 7200 604800 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0