Apex domains cannot have CNAME records.
Question and response
Question
dig munimetrics.org. NS
Answer
munimetrics.org. 5 NS ns-1989.awsdns-56.co.uk.
munimetrics.org. 5 NS ns-251.awsdns-31.com.
munimetrics.org. 5 NS ns-125.awsdns-15.com.
munimetrics.org. 5 NS ns-166.awsdns-20.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0