Apex domains cannot have CNAME records.
Question and response
Question
dig acme.nfbcal.org. NS
Answer
acme.nfbcal.org. 4 NS ns.VIA.NET.
acme.nfbcal.org. 4 NS ns4.ZOCALO.NET.
acme.nfbcal.org. 4 NS ns.NFBCAL.ORG.
acme.nfbcal.org. 4 NS ns2.VIA.NET.
acme.nfbcal.org. 4 NS ns3.VIA.NET.
Authority
The response has no authority records.
Additional
ns.nfbcal.org. 3 A 45.79.226.29
ns4.zocalo.net. 3 A 128.114.129.105
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0