Apex domains cannot have CNAME records.
Question and response
Question
dig pl-waw-2.baremetal.scw.cloud. NS
Answer
pl-waw-2.baremetal.scw.cloud. 1 NS ns0.dom.scw.cloud.
pl-waw-2.baremetal.scw.cloud. 1 NS ns1.dom.scw.cloud.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0