Apex domains cannot have CNAME records.
Question and response
Question
dig bancotui.com. NS
Answer
bancotui.com. 5 NS dns2.cloud.claro.com.do.
bancotui.com. 5 NS dns1.cloud.claro.com.do.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0