Apex domains cannot have CNAME records.
Question and response
Question
dig mdicare.org. NS
Answer
mdicare.org. 2 NS ns-1100.awsdns-09.org.
mdicare.org. 2 NS ns-872.awsdns-45.net.
mdicare.org. 2 NS ns-4.awsdns-00.com.
mdicare.org. 2 NS ns-1133.awsdns-13.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0