Standalone: UR28M keeps shutting down

Hi - Sometimes I like to leave my computer off, and just play my synth through my UR28M.

Though I never have problems when my computer is on and the DAW is up and running, when I just play the synth through the UR28M it will invariably shut down, and the sound goes away.

By shut down, I mean all the green and red lights go away, and the only button that is lit is the power button, and it is only “half lit” like it looks like when it is plugged in but before it is depressed to power up the unit.

Anyone have any suggestions?


^^ Any ideas please, anyone?