No idea 'why'. It was working fine until I moved it, then nothing. On its own display, it looks like its trying, but it's set to 24V (not auto), so just thinks the battery is flat.Why not? What behavior are you seeing?
As for the behaviour, it 'looks' normal, but no comms out the RS485 port.
I've tried the MT50, the USB cable and a RS485-Ethernet bridge - nothing.