Apex domains cannot have CNAME records.
Question and response
Question
dig xsend9.email. NS
Answer
xsend9.email. 1 NS ns-1336.awsdns-39.org.
xsend9.email. 1 NS ns-1646.awsdns-13.co.uk.
xsend9.email. 1 NS ns-450.awsdns-56.com.
xsend9.email. 1 NS ns-923.awsdns-51.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0