Apex domains cannot have CNAME records.
Question and response
Question
dig rushlimbauh.com. NS
Answer
rushlimbauh.com. 5 NS ns-1696.awsdns-20.co.uk.
rushlimbauh.com. 5 NS ns-471.awsdns-58.com.
rushlimbauh.com. 5 NS ns-650.awsdns-17.net.
rushlimbauh.com. 5 NS ns-1614.awsdns-09.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0