ns1.sprintdatacenter.pl has no MX records.
Question and response
Question
dig ns1.sprintdatacenter.pl. MX
Answer
The response has no answer records.
Authority
sprintdatacenter.pl. 3600 SOA ns1.sprintdatacenter.pl. dns.sprint.com.pl. 2025101501 3600 3600 1209600 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0