Apex domains cannot have CNAME records.
Question and response
Question
dig americandatanetworks.com. NS
Answer
americandatanetworks.com. 5 NS ns-315.awsdns-39.com.
americandatanetworks.com. 5 NS ns-1120.awsdns-12.org.
americandatanetworks.com. 5 NS ns-661.awsdns-18.net.
americandatanetworks.com. 5 NS ns-1541.awsdns-00.co.uk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0