Apex domains cannot have CNAME records.
Question and response
Question
dig zerchain.com. NS
Answer
zerchain.com. 3 NS dns1.interdominios.com.
zerchain.com. 3 NS dns2.interdominios.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0