Apex domains cannot have CNAME records.
Question and response
Question
dig orange.sn. NS
Answer
orange.sn. 4 NS ns1.sonatel.sn.
orange.sn. 4 NS ns2.sonatel.sn.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0