Apex domains cannot have CNAME records.
Question and response
Question
dig corrivo.io. NS
Answer
corrivo.io. 5 NS ns-1328.awsdns-38.org.
corrivo.io. 5 NS ns-944.awsdns-54.net.
corrivo.io. 5 NS ns-85.awsdns-10.com.
corrivo.io. 5 NS ns-1804.awsdns-33.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0