Apex domains cannot have CNAME records.
Question and response
Question
dig canalmed.org. NS
Answer
canalmed.org. 5 NS ns-529.awsdns-02.net.
canalmed.org. 5 NS ns-721.awsdns-26.net.
canalmed.org. 5 NS ns-1319.awsdns-36.org.
canalmed.org. 5 NS ns-119.awsdns-14.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0