we have a RUTX09 with the latest firmware on it - below the relevant section from the troubleshoot backup:
The issue is, that the device is able to connect flawlessly via LTE but then does not seem to get an answer from the net - The connection statistics also show that there is no data received but sent. I tried it with several SIM cards which work on other devices and I tried them on both SIM slots.
I did a packet trace on the WAN interface which just shows outgoing DNS queries but to answers. Did several factory resets and re-flashed the firmware (not the modem firmware which I cannot do without Internet connection).
I am really glad if this can be solved even with finally diagnosing a hardware failure and replace the device.