Apex domains cannot have CNAME records.
Question and response
Question
dig rdsnet.tech. NS
Answer
rdsnet.tech. 5 NS ns.rdsnet.tech.
rdsnet.tech. 5 NS ns.rdsnet.org.
rdsnet.tech. 5 NS ns.rdsnet.ro.
Authority
The response has no authority records.
Additional
ns.rdsnet.tech. 5 A 188.27.120.12
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0