Apex domains cannot have CNAME records.
Question and response
Question
dig socketlabs.com. NS
Answer
socketlabs.com. 4 NS ns-1718.awsdns-22.co.uk.
socketlabs.com. 4 NS ns-1372.awsdns-43.org.
socketlabs.com. 4 NS ns-88.awsdns-11.com.
socketlabs.com. 4 NS ns-929.awsdns-52.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0