Apex domains cannot have CNAME records.
Question and response
Question
dig tigo.com.co. NS
Answer
tigo.com.co. 4 NS lauta.une.net.co.
tigo.com.co. 4 NS nsbog01.une.net.co.
tigo.com.co. 4 NS birlocha.une.net.co.
Authority
The response has no authority records.
Additional
lauta.une.net.co. 4 A 200.13.224.2
nsbog01.UNE.NET.CO. 4 A 200.31.208.100
birlocha.une.net.co. 4 A 200.13.224.3
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0