www.tvk-net.pl has no MX records.
Question and response
Question
dig www.tvk-net.pl. MX
Answer
The response has no answer records.
Authority
tvk-net.pl. 86400 SOA tvk-net.pl. root.tvk-net.pl. 2025021801 10800 900 604800 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0