Apex domains cannot have CNAME records.
Question and response
Question
dig emailbytelephone.com. NS
Answer
emailbytelephone.com. 5 NS ns2.emailbytelephone.com.
emailbytelephone.com. 5 NS ns1.emailbytelephone.com.
Authority
The response has no authority records.
Additional
ns1.emailbytelephone.com. 5 A 212.32.248.113
ns2.emailbytelephone.com. 5 A 213.227.157.17
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0