It is possible that your device may not work properly after an update or something else.
Please make a few checks beforehand:
Check the power supply, make it 12 V, ;
Check if .Net framework is installed and up to date. ;
You can check here: https://wiki.teltonika-gps.com/view/FMB640_First_Start#PC_Connection_.28Windows.29
...
Please, try to use another power supply. ;
If external voltage is correct, please, check if device is visible in device manager,;
It is possible that the firmware is not supported by the configurator.;
You can check here:
https://wiki.teltonika-gps.com/view/Teltonika_Configurator_versions#For_FMB640
After checking the different instructions above
...
:
You can contact the support (support@mirifica.de) to have the “Firmware Updater” that will allow you to flash your device.
How to make a hard reset:
You can manually reset device by plugging device power OFF and back ON, Unplug the connector.