smtp.encryptedemail.usa.net has no MX records.
Question and response
Question
dig smtp.encryptedemail.usa.net. MX
Answer
The response has no answer records.
Authority
encryptedemail.usa.net. 3600 SOA cndvg001.usa.net. hostmaster.usa.net. 2010112000 1800 600 604800 3600
Additional
. 0 OPT ; payload 512, xrcode 0, version 0, flags 0