cgp.vtr.net has no MX records.
Question and response
Question
dig cgp.vtr.net. MX
Answer
The response has no answer records.
Authority
cgp.vtr.net. 300 SOA ns00.vtr.net. hostmaster.vtr.net. 2011101800 10800 3600 604800 38400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0