Please do the following check:

• Make sure there are no obstructions in the way of the IR receiver on the device.
• Move closer to the receiver (within 23 feet) or change the angle (within 30 degrees) to the receiver.
• Replace the batteries. Even if lights on the remote control are on, weak batteries may still cause the remote control to operate intermittently.

If above check doesn’t help, please contact ViewSonic service center.