Please follow the steps to fix the issue.
1.Please press the Voice Search button on the remote to check that it is
connected to the BenQ QS02.
2.If your remote is not connected to the BenQ QS02, please restart your
projector to enter the Bluetooth pairing process, and go to Step 3 if your
remote successfully connects to the BenQ QS02 after rebooting.
3.Press and hold the Play/Pause button on your remote if your remote is
connected to the BenQ QS02.
4.Then, press the Navigation and OK buttons to go to Settings >
Device Preference > Display & Sound > HDMI CEC > CEC, and turn on
CEC if it isn't enabled already.
Restart your projector to complete the process.
5.If the problem persists after the above steps, please disconnect other
devices connected to the projector and keep only the QS02.