THRU 16 not sending to midi outs

Hi,

I have a THRU-16 connected to my PC via 5-Pin DIN. When this DIN is connected to any MIDI device directly, the device responds; when I insert the THRU 16 in between, so, PC > Thru-16 > MIDI device (output 6, ch.6), the input indicator flashes on the THRU-16, but the output indicator does not illuminate and the downstream MIDI device does not respond.

I have configured the THRU-16 so each output responds to all 16 channels, the PC is sending the same channel as the downstream MIDI device (channel 6), the MIDI switches have been turned on, there is no filtering going on. I have tested this with many devices, without the THRU-16 and on each output, the PC controls the devices fine via 5-pin DIN directly, however, whenever the THRU-16 is used to split the signal, the device input lights up but does not send the signal to the outputs.

The device is powered with the supplied cable to a wall adapter, I have tried running the THRU-16 from the USB port connected to the PC, I have tried disconnecting the 5 PIN DIN and assigning the channel through the DAW (Reaper). In all instances, it responds at the input light but does not send to the outputs...please help.