Apex domains cannot have CNAME records.
Question and response
Question
dig user.ono.com. NS
Answer
user.ono.com. 1 NS dns03.ono.com.
user.ono.com. 1 NS dns02.ono.com.
user.ono.com. 1 NS dns01.ono.com.
Authority
The response has no authority records.
Additional
dns01.ono.com. 1 A 62.42.230.135
dns02.ono.com. 1 A 62.42.230.136
dns03.ono.com. 1 A 62.42.63.51
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0