Could you confirm if you were sending the SMS commands with 2 spaces or a space before the command? It is also, worth checking if there were any passwords or Authorized numbers that were configured in the device Configuration.
Otherwise, if there were no number set. We would like to analyze your issue, please send all the details to the helpdesk or contact your sales.
The details include the following.
Device IMEI.
Configuration file.
Device Logs and Dump files
If you don’t have any contacts with our Sales managers or do not have an HD account, please get in touch with them on our official website https://teltonika-gps.com/ and click on the “Contact Us” button. When you click, please fill out the form and submit it.