Apex domains cannot have CNAME records.
Question and response
Question
dig ppepost.net. NS
Answer
ppepost.net. 4 NS ns-1936.awsdns-50.co.uk.
ppepost.net. 4 NS ns-1135.awsdns-13.org.
ppepost.net. 4 NS ns-438.awsdns-54.com.
ppepost.net. 4 NS ns-948.awsdns-54.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0