This is due to the multimedia function being locked. Hold Fn+Esc for about 3 to 5 seconds to unlock.
KUS015 Wireless Keyboard & Mouse Combo
Press Esc+Q on the keyboard and check if the indicator flashes. If yes, the keyboard itself is fine, there may be something wrong with the cable. If not, please contact us.
KUS015 Bluetooth Version
Press Fn+C to start pairing.