spamv.megared.com.mx has no CNAME records.
Question and response
Question
dig spamv.megared.com.mx. NS
Answer
The response has no answer records.
Authority
megared.com.mx. 600 SOA unix1.megared.net.mx. root.unix1.megared.net.mx. 113 3600 900 604800 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0