Apex domains cannot have CNAME records.
Question and response
Question
dig ehealthcaresymposium.com. NS
Answer
ehealthcaresymposium.com. 5 NS ns8.dnsmadeeasy.com.azure-dns.info.
ehealthcaresymposium.com. 5 NS ns7.dnsmadeeasy.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0