Hello,
Kindly check if your device is powered on, and make sure it has internet connectivity.
If the issue still occurs, kindly remove the device and add it again to your RMS account.
Lastly, Although Teltonika devices have RMS service enabled by default, set the Connection type field to Enabled on the device WebUI. You can navigate through Services → Cloud Solutions → RMS.
Let me know the results.
Best regards,
Robert