ns3.strends.com.mx has no CNAME records.
Question and response
Question
dig ns3.strends.com.mx. NS
Answer
The response has no answer records.
Authority
strends.com.mx. 10755 SOA ns1.strends.com.mx. hostmaster.strends.com.mx. 2012080100 10800 3600 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0