Could the positions of the transmitter and receiver be backwards? For example, the wireless receiver connected to the pre-out and the wireless transmitter connected to the subwoofer? If this is the case, it could cause what you are experiencing, and you would have to switch them so that the transmitter is connected to the pre-out.

If this isn't the case, please reach out at support.outlawaudio.com, so we can be of further assistance.