Apex domains cannot have CNAME records.
Question and response
Question
dig myvanlab.descartes.com. NS
Answer
myvanlab.descartes.com. 5 NS ns-1337.awsdns-39.org.
myvanlab.descartes.com. 5 NS ns-1673.awsdns-17.co.uk.
myvanlab.descartes.com. 5 NS ns-379.awsdns-47.com.
myvanlab.descartes.com. 5 NS ns-1020.awsdns-63.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0