ms01.mailsafe.usa.net has no MX records.
Question and response
Question
dig ms01.mailsafe.usa.net. MX
Answer
The response has no answer records.
Authority
mailsafe.usa.net. 3600 SOA cndvg001.usa.net. hostmaster.usa.net. 2026021801 1800 600 604800 3600
Additional
. 0 OPT ; payload 512, xrcode 0, version 0, flags 0