Apex domains cannot have CNAME records.
Question and response
Question
dig fused.email. NS
Answer
fused.email. 5 NS ns-204.awsdns-25.com.
fused.email. 5 NS ns-986.awsdns-59.net.
fused.email. 5 NS ns-1131.awsdns-13.org.
fused.email. 5 NS ns-1734.awsdns-24.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0