Apex domains cannot have CNAME records.
Question and response
Question
dig docebopaas.com. NS
Answer
docebopaas.com. 5 NS ns-1927.awsdns-48.co.uk.
docebopaas.com. 5 NS ns-1262.awsdns-29.org.
docebopaas.com. 5 NS ns-289.awsdns-36.com.
docebopaas.com. 5 NS ns-572.awsdns-07.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0