ben-shepherd

Check battery orientation - Remove and reinsert batteries, ensuring they're placed in the correct +/- direction.

Try fresh batteries - Even if the current ones are relatively new, test with known working batteries.

Check the USB receiver - Remove and reinsert the wireless receiver into a different USB port. Try a port directly on your computer rather than through a hub.

Distance and interference - Move the keyboard closer to the receiver and ensure there are no large metal objects or other wireless devices between them.

Re-pair the keyboard - Look for a small reset or connect button on both the keyboard and receiver (usually marked with a ⟳ or ∞ symbol). Press these to establish a new connection.