Apex domains cannot have CNAME records.
Question and response
Question
dig abnormal-email.com. NS
Answer
abnormal-email.com. 4 NS ns-1259.awsdns-29.org.
abnormal-email.com. 4 NS ns-101.awsdns-12.com.
abnormal-email.com. 4 NS ns-715.awsdns-25.net.
abnormal-email.com. 4 NS ns-2030.awsdns-61.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0