Apex domains cannot have CNAME records.
Question and response
Question
dig fiberway.pl. NS
Answer
fiberway.pl. 4 NS fns1.42.pl.
fiberway.pl. 4 NS fns2.42.pl.
fiberway.pl. 4 NS ns3.fiberway.pl.
fiberway.pl. 4 NS ns2.fiberway.pl.
fiberway.pl. 4 NS ns1.fiberway.pl.
Authority
The response has no authority records.
Additional
ns1.fiberway.pl. 4 A 91.218.211.218
ns2.fiberway.pl. 4 A 91.218.203.58
ns3.fiberway.pl. 4 A 91.218.203.38
fns1.42.pl. 4 A 79.98.145.34
fns2.42.pl. 4 A 51.38.99.90
fns2.42.pl. 4 AAAA 2001:41d0:701:1100:0:0:0:66c
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0