Apex domains cannot have CNAME records.
Question and response
Question
dig eastua.net. NS
Answer
eastua.net. 5 NS ns.sm.ua.
eastua.net. 5 NS ns.eastua.net.
eastua.net. 5 NS nsd.as15800.net.
eastua.net. 5 NS nsk.as15800.net.
eastua.net. 5 NS ns.zp.ua.
Authority
The response has no authority records.
Additional
ns.eastua.net. 5 A 31.28.166.180
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0