Apex domains cannot have CNAME records.
Question and response
Question
dig vexinavro.com. NS
Answer
vexinavro.com. 5 NS ns-1720.awsdns-23.co.uk.
vexinavro.com. 5 NS ns-382.awsdns-47.com.
vexinavro.com. 5 NS ns-646.awsdns-16.net.
vexinavro.com. 5 NS ns-1948.awsdns-51.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0