Apex domains cannot have CNAME records.
Question and response
Question
dig buk.lt. NS
Answer
buk.lt. 5 NS ns2.domreg.lt.
buk.lt. 5 NS ns2.kli.lt.
buk.lt. 5 NS ns1.kli.lt.
Authority
The response has no authority records.
Additional
ns1.kli.lt. 5 A 46.36.66.66
ns2.domreg.lt. 5 A 83.171.8.8
ns2.domreg.lt. 5 AAAA 2001:778:0:8:0:0:0:8
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0