Apex domains cannot have CNAME records.
Question and response
Question
dig nursebrownnrg4us.com. NS
Answer
nursebrownnrg4us.com. 5 NS ns-1370.awsdns-43.org.
nursebrownnrg4us.com. 5 NS ns-974.awsdns-57.net.
nursebrownnrg4us.com. 5 NS ns-335.awsdns-41.com.
nursebrownnrg4us.com. 5 NS ns-1616.awsdns-10.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0