Apex domains cannot have CNAME records.
Question and response
Question
dig medicuredelivery.com. NS
Answer
medicuredelivery.com. 5 NS ns-510.awsdns-63.com.
medicuredelivery.com. 5 NS ns-408.awsdns-51.com.
medicuredelivery.com. 5 NS ns-1324.awsdns-37.org.
medicuredelivery.com. 5 NS ns-597.awsdns-10.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0