When you install Windows 10, it lets you use it for a certain period of time without any problem even if it is not genuine. It offers grace period so you can get a valid license to activate it. However, if you recieve activation error code 0xC004F064 with message

The Software Protection Service reported that the non-genuine grace period expired

The MAK key you have used to activate Windows is not valid. Windows comes with Activation tools to check if the system is genuine. Your ill need to get a genuine MAK key to activate your computer.