keyboard db900 losing connection

keyboard db900 losing connection.

1. keyboard does work all the time but i can hear windows usb disconnect/connect sound time to time.
2. when opening dell peripheral manager, it says keyboard is disconnected sometimes. even though keyboard does work wirelessly.
3. when dell peripheral manager says disconnected, my custom shortcuts F1-F12 buttons doesnt work.
4. dell peripheral manager shows a tutorial on how to reconnect keyboard but it doesnt work. im forced to disconnect and reconnect usb-dongle.

why is this happening? is the issue keyboard, usb-dongle or software related?