ns2.internetdsl.pl has no MX records.
Question and response
Question
dig ns2.internetdsl.pl. MX
Answer
The response has no answer records.
Authority
internetdsl.pl. 3600 SOA ns1.internetdsl.pl. dns.internetdsl.pl. 1701367962 172800 3600 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0