Apex domains cannot have CNAME records.
Question and response
Question
dig tigoune.com.co. NS
Answer
tigoune.com.co. 3 NS birlocha.une.net.co.
tigoune.com.co. 3 NS nsbog01.une.net.co.
tigoune.com.co. 3 NS lauta.une.net.co.
Authority
The response has no authority records.
Additional
lauta.une.net.co. 3 A 200.13.224.2
nsbog01.une.net.co. 3 A 200.31.208.100
birlocha.une.net.co. 3 A 200.13.224.3
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0