Apex domains cannot have CNAME records.
Question and response
Question
dig helmes.com. NS
Answer
helmes.com. 5 NS ns4.helmes.ee.
helmes.com. 5 NS ns3.helmes.ee.
helmes.com. 5 NS ns1.helmes.ee.
helmes.com. 5 NS ns2.helmes.ee.
Authority
The response has no authority records.
Additional
ns1.helmes.ee. 5 A 95.215.132.100
ns2.helmes.ee. 5 A 95.215.133.100
ns3.helmes.ee. 5 A 20.107.209.108
ns4.helmes.ee. 5 A 20.91.185.146
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0