Apex domains cannot have CNAME records.
Question and response
Question
dig aventri.com. NS
Answer
aventri.com. 5 NS ns-1311.awsdns-35.org.
aventri.com. 5 NS ns-626.awsdns-14.net.
aventri.com. 5 NS ns-175.awsdns-21.com.
aventri.com. 5 NS ns-1557.awsdns-02.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0