Problem with SMS messages

Hello, I am having a simple problem with SMS messages being sent to my Tmobile phones. I did a manual telnet into my mail server that sends these messages and found that the ones that are coming from hobbit at xxx are failing. But when I use my own From address Myemail at cmcflex.com the messages go through with no issues. Any suggestions on approaches I can take to fixing this problem. Or how could I change the from sender on the hobbit server?

Thank you for your time.

Frank