DIAGNOSIS The remote's IR signal isn't reaching the soundbar's sensor, or the remote batteries are dead. Obstruction or distance is the most common cause.
FIX Replace the two AAA batteries in the remote. Ensure you're pointing the remote directly at the front center of the soundbar from within 20 feet, with a clear line of sight. Remove any objects blocking the IR sensor on the soundbar.
IF THAT DIDN'T WORK Test if the remote is emitting a signal. Use your phone's camera in video mode. Point the remote's LED at the phone camera and press a button. You should see a faint purple light flash on your screen. No light means a dead remote.
HEADS UP Strong ambient light, especially from direct sunlight or some LED bulbs, can flood the IR sensor and block the signal. Try adjusting your lighting.