km7120w keyboard not responding sometimes

Dear All,

Recently I have purchased km7120w keyboard and mouse. Facing some issue and also hve some query. 

1. Do I need to turn off keyboard and mouse daily? Or the auto turned off feature is there.

2. Which both are connected via USB dongle, some times the keyboard is unresponsive, same time mouse is working fine. how to fix the issue.

Could you please able to help.

Thanks,

Arijit