Apex domains cannot have CNAME records.
Question and response
Question
dig mydeckstain.com. NS
Answer
mydeckstain.com. 5 NS ns-1361.awsdns-42.org.
mydeckstain.com. 5 NS ns-1499.awsdns-59.org.
mydeckstain.com. 5 NS ns-1825.awsdns-36.co.uk.
mydeckstain.com. 5 NS ns-120.awsdns-15.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0