Apex domains cannot have CNAME records.
Question and response
Question
dig er-com.net. NS
Answer
er-com.net. 5 NS ns2.er-com.net.
er-com.net. 5 NS ns.er-com.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0