Apex domains cannot have CNAME records.
Question and response
Question
dig descartesservices.com. NS
Answer
descartesservices.com. 5 NS ns-879.awsdns-45.net.
descartesservices.com. 5 NS ns-1311.awsdns-35.org.
descartesservices.com. 5 NS ns-1878.awsdns-42.co.uk.
descartesservices.com. 5 NS ns-241.awsdns-30.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0