Apex domains cannot have CNAME records.
Question and response
Question
dig acupastor.com. NS
Answer
acupastor.com. 4 NS ns-327.awsdns-40.com.
acupastor.com. 4 NS ns-1259.awsdns-29.org.
acupastor.com. 4 NS ns-626.awsdns-14.net.
acupastor.com. 4 NS ns-1583.awsdns-05.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0