Apex domains cannot have CNAME records.
Question and response
Question
dig add-online.com. NS
Answer
add-online.com. 2 NS ns1.add-online.com.
add-online.com. 2 NS ns2.add-online.com.
Authority
The response has no authority records.
Additional
ns1.add-online.com. 2 A 195.28.200.101
ns2.add-online.com. 2 A 178.23.155.191
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0