The verification test message displays a test pattern on the status indicator but no response SMS message is received.

This could mean there is a problem with the SIM operating on the network because it could receive the test message but not send a response. If the network error (transmit fault) code is displayed after the test pattern then the network could not process the response message usually for one of these reasons: There is no credit on the SIM or mobile account. The SIM is incorrectly provisioned (some data-only SIMs cannot send SMS messages)The SMS service number (SMSC) is incorrect. The mobile network is busy. The SIM can be checked in a phone by sending a message from the phone. This will usually also set up the SMSC number if it is not correctly programmed in the SIM. Make sure the message is sent via SMS and not a messaging app (which typically uses data and not SMS). If the network is busy, wait a while and try again. If the problem continues try sending a message from your phone where the SMS Lite is located. If this succeeds the network is not busy and this is not the problem. Look for other error codes being displayed on the SMS Lite status indicator. Then see below. Remove the lid on the SMS Lite and check that the LED indicator on the modem daughterboard is flashing on and off slowly. If it is not then the device has not registered on the mobile network.