Apex domains cannot have CNAME records.
Question and response
Question
dig olc-fm.org. NS
Answer
olc-fm.org. 5 NS ns-622.awsdns-13.net.
olc-fm.org. 5 NS ns-143.awsdns-17.com.
olc-fm.org. 5 NS ns-446.awsdns-55.com.
olc-fm.org. 5 NS ns-1304.awsdns-35.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0