Apex domains cannot have CNAME records.
Question and response
Question
dig tedm.email. NS
Answer
tedm.email. 2 NS ns-1797.awsdns-32.co.uk.
tedm.email. 2 NS ns-1336.awsdns-39.org.
tedm.email. 2 NS ns-261.awsdns-32.com.
tedm.email. 2 NS ns-753.awsdns-30.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0