A. Please check if the battery is installed correctly and has power.
B. Please check if your camera infrared remote mode is turned on.
C. Suppose your lens is under AF mode, please make sure your camera is in focus status.
D. The working distance for infrared remote control is limited, please make sure your use is within the effective working distance mentioned in the manual.
E. Please make sure the camera is able to receive infrared signal from the remote control without any block or interference.