Apex domains cannot have CNAME records.
Question and response
Question
dig customercast.com. NS
Answer
customercast.com. 5 NS ns-924.awsdns-51.net.
customercast.com. 5 NS ns-466.awsdns-58.com.
customercast.com. 5 NS ns-1987.awsdns-56.co.uk.
customercast.com. 5 NS ns-1150.awsdns-15.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0