Apex domains cannot have CNAME records.
Question and response
Question
dig wistarip.com.mx. NS
Answer
wistarip.com.mx. 5 NS cloud2.triara.com.
wistarip.com.mx. 5 NS cloud1.triara.com.
wistarip.com.mx. 5 NS cloud3.triara.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0