Apex domains cannot have CNAME records.
Question and response
Question
dig arma3.su. NS
Answer
arma3.su. 4 NS ns2.example.com.
arma3.su. 4 NS ns1.example.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0