smtp.digitalagent.net has no MX records.
Question and response
Question
dig smtp.digitalagent.net. MX
Answer
The response has no answer records.
Authority
digitalagent.net. 300 SOA ns2.exsbs.net. hostmaster.digitalagent.net. 2005043548 300 300 300 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0