Apex domains cannot have CNAME records.
Question and response
Question
dig email.mirakl.net. NS
Answer
email.mirakl.net. 5 NS ns-1397.awsdns-46.org.
email.mirakl.net. 5 NS ns-704.awsdns-24.net.
email.mirakl.net. 5 NS ns-419.awsdns-52.com.
email.mirakl.net. 5 NS ns-1967.awsdns-53.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0