mail.task.gda.pl has no CNAME records.
Question and response
Question
dig mail.task.gda.pl. NS
Answer
The response has no answer records.
Authority
task.gda.pl. 3434 SOA ns1.task.gda.pl. dns.task.gda.pl. 2026010201 10800 3600 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0