Apex domains cannot have CNAME records.
Question and response
Question
dig smartmaster.lt. NS
Answer
smartmaster.lt. 5 NS wexio.dns.swip.net.
smartmaster.lt. 5 NS pitea.dns.swip.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0