Diagnosis
Weak batteries in the remote or an obstructed IR sensor on the fan. This model's IR receiver is somewhat directional.
How to Fix It
Replace the remote's batteries with fresh CR2025 coin cells. Then, point the remote directly at the IR sensor window, which is the small, dark plastic rectangle on the front control panel, not the LED display.
If That Didn't Work
The IR sensor on the fan might be dusty. Unplug the fan and gently clean the dark sensor window on the front with a dry cotton swab.
Heads Up
Bright sunlight or direct light from certain LED bulbs can flood the IR sensor and interfere with the signal. Try using it in different lighting conditions.