mx2.v103.vh.net.pl has no CNAME records.
Question and response
Question
dig mx2.v103.vh.net.pl. NS
Answer
The response has no answer records.
Authority
v103.vh.net.pl. 9982 SOA ns1.vh.pl. mm.wdma.pl. 2025112800 3600 1800 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0