There are several things that can cause your remote control to not function properly.
The remote control’s batteries may not be installed correctly or may be low on power. To change the batteries, see Replacing the Batteries.
Make sure you are within about 20 feet (6 meters) of the projector and within range of the projector’s front or back sensor (approximately 30° to the left or right and 15° above or below).
Dim the room lights and turn off any fluorescent lights. Make sure the projector is not in direct sunlight. Strong lighting, especially fluorescent lights, may affect the projector’s infrared receivers. Also, turn off any nearby equipment that emits infrared energy, such as a radiant room heater. If necessary, use the Remote Receiver setting to disable the projector’s front or back sensor if it continues to pick up interference. See Customizing Projector Features.