Apex domains cannot have CNAME records.
Question and response
Question
dig avature.net. NS
Answer
avature.net. 5 NS ns-1704.awsdns-21.co.uk.
avature.net. 5 NS ns-440.awsdns-55.com.
avature.net. 5 NS ns-753.awsdns-30.net.
avature.net. 5 NS ns-1066.awsdns-05.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0