mail.matcom.com.pl has no CNAME records.
Question and response
Question
dig mail.matcom.com.pl. NS
Answer
The response has no answer records.
Authority
matcom.com.pl. 6474 SOA ns1.matcom.com.pl. hostmaster.matcom.com.pl. 2026022500 14400 7200 1209600 7200
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0