mail.lh.pl has no CNAME records.
Question and response
Question
dig mail.lh.pl. NS
Answer
The response has no answer records.
Authority
lh.pl. 6439 SOA ns.lh.pl. root.lh.pl. 2008052701 1200 600 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0