MIDI 1U not working?

Hi, trying to connect a new MIDI 1U to my palette case - the 4 vertical lights go a solid green/yellow/green/yellow and won’t budge.

The system reset sequence, holding CLK+ down during power up, has no effect either. Lights stay and there is no reaction from the CLK or LEARN lights.

When I connect external MIDI on ch1, that has no effect either. Nothing coming from the ouputs.

Have tried to connect the config app and the firmware updater, they are not seeing the device.

All suggestions welcome. Currently suffering from eurorack-user-guide-itis, so I may have missed something obvious.

Thanks, Paul.