Apex domains cannot have CNAME records.
Question and response
Question
dig raistech.net. NS
Answer
raistech.net. 5 NS ns-2041.awsdns-63.co.uk.
raistech.net. 5 NS ns-1307.awsdns-35.org.
raistech.net. 5 NS ns-264.awsdns-33.com.
raistech.net. 5 NS ns-646.awsdns-16.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0