Apex domains cannot have CNAME records.
Question and response
Question
dig mediasystem-tdi.pl. NS
Answer
mediasystem-tdi.pl. 4 NS dns1.mediasystem-tdi.pl.
mediasystem-tdi.pl. 4 NS dns2.mediasystem-tdi.pl.
Authority
The response has no authority records.
Additional
dns1.mediasystem-tdi.pl. 4 A 185.231.13.10
dns2.mediasystem-tdi.pl. 4 A 185.231.13.12
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0