webmail.cotas.com.bo has no CNAME records.
Question and response
Question
dig webmail.cotas.com.bo. NS
Answer
The response has no answer records.
Authority
cotas.com.bo. 10430 SOA dns1.cotas.com.bo. postmaster.com.bo. 1989020550 10800 3600 3600000 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0