DIAGNOSIS: The remote uses Bluetooth for voice control and some functions, but basic navigation still relies on an infrared (IR) signal. Something is blocking the IR receiver on the TV, or the remote's batteries are weak.
FIX: 1) Replace the batteries in the remote with fresh, name-brand ones. The cheap ones that come with the TV don't last. 2) Check the IR receiver on the TV. It's a small, dark plastic window, usually on the bottom center of the bezel. Make sure it's not covered by a soundbar, a figurine, or even dust. Wipe it clean with a dry cloth. 3) Move any bright lights, like a floor lamp, away from the front of the TV. Incandescent bulbs can flood the room with infrared light and drown out the remote's signal.
IF THAT DIDN'T WORK: The remote itself might be faulty. Try using the Hisense Remote Now app on your smartphone as a test. If that works perfectly, the physical remote is the problem. Contact Hisense for a replacement remote under warranty.
HEADS UP: If you're using a universal remote or a soundbar remote that controls the TV via HDMI-CEC, those can sometimes send conflicting signals that make the TV's own remote seem unresponsive. Try turning off CEC (called 'HDMI Control' or 'AnyNet+' in settings) temporarily to test.