Hi,
Make sure the TRB140 is updated and the SMS Utilities rules are enabled.
Review Event log entries via the Web Ui Status> Logs page. Are there any related records that the SMS was received by gateway and that it tried to send it back?
Check if the SMS message is coming to the gateway and also try to send at least one message. You can do this on the Web UI Services> Mobile Utilities> Messages page.
Regards.