Keyboard and mouse not working but on

This sounds like it could be from not having a charge and sync cable. Are you using the Micro USB that came in the box as the cable that is connecting the K2 to the controller? Make sure you remove the batteries if the controller has any prior to connecting.

Also, be sure you are set to KM Emulation located at the very top of the K2 App.

The cable that comes with the box (micro usb) does not fit in xbox series s/x controllers.