mx1.iq.pl has no CNAME records.
Question and response
Question
dig mx1.iq.pl. NS
Answer
The response has no answer records.
Authority
iq.pl. 3576 SOA ns1.iq.pl. dns.iq.pl. 2026021301 10800 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0