Apex domains cannot have CNAME records.
Question and response
Question
dig exerciserelieve.net. NS
Answer
exerciserelieve.net. 4 NS ns2fwz.name.com.
exerciserelieve.net. 4 NS ns4clq.name.com.
exerciserelieve.net. 4 NS ns1dns.name.com.
exerciserelieve.net. 4 NS ns3bfm.name.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0