Apex domains cannot have CNAME records.
Question and response
Question
dig computec.com. NS
Answer
computec.com. 4 NS ns1.impsat.net.co.
computec.com. 4 NS juno.impsat.net.co.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0