Apex domains cannot have CNAME records.
Question and response
Question
dig gripp.com. NS
Answer
gripp.com. 5 NS ns-921.awsdns-51.net.
gripp.com. 5 NS ns-148.awsdns-18.com.
gripp.com. 5 NS ns-1963.awsdns-53.co.uk.
gripp.com. 5 NS ns-1447.awsdns-52.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0