Apex domains cannot have CNAME records.
Question and response
Question
dig yhmsilicone.com. NS
Answer
yhmsilicone.com. 5 NS ns-1542.awsdns-00.co.uk.
yhmsilicone.com. 5 NS ns-1944.awsdns-51.co.uk.
yhmsilicone.com. 5 NS ns-1987.awsdns-56.co.uk.
yhmsilicone.com. 5 NS ns-1252.awsdns-28.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0