There are a couple of approaches to resolving this issue:
Of course, the very first step should be to ensure that your device firmware is on the latest (or at least the latest mass production firmware) version. Said firmware updates can be found in our Wiki or under System > Firmware > Update Firmware if the device has internet.
If you don’t want to reset the device and lose your configurations yet, then you would have to check the status of the internal modem when the error happens by accessing the SSH (CLI) of the device and entering the following:
lsusb
The output should then give you the codes for the modem, where you should be able to check if the modem is in EDL mode (code is 9008)
If you see this number, you may resolve this issue with a modem firmware update if one is available. If not, move on to step 3.
Bootloader resetting the device. This is a hard reset that can be done on most of our devices that have an OS on them. The explanation & steps of the bootloader process can be found under this link: https://wiki.teltonika-networks.com/view/Bootloader_menu
Final course of action if all else fails, would be to contact your supplier for either an exchange, or a repair (assuming the warranty is valid) - if you haven’t bought the device directly from us. If you did buy from us, then contacting your sales manager would be the way to go, they would then get in touch with our engineers and the process would escalate further, assuming that the warranty is valid.
Thx for response.
Firmware has been up to date nearly in all occasions and have tried resetting, but only by using the reset button in web access.
Waiting for a chance to test resolves 2 and 3.