Apex domains cannot have CNAME records.
Question and response
Question
dig gigaclear.com. NS
Answer
gigaclear.com. 5 NS ns-998.awsdns-60.net.
gigaclear.com. 5 NS ns-1134.awsdns-13.org.
gigaclear.com. 5 NS ns-1615.awsdns-09.co.uk.
gigaclear.com. 5 NS ns-38.awsdns-04.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0