On your raspberry pi command prompt execute the following command:

  sudo raspi-config

This will bring on a small menu from which you should choose the following option:

  Interfacing Options  Configure connections to peripherals

This will bring another menu from which you should choose the following option:

  P1 Camera      Enable/Disable connection to the Raspberry Pi Camera

Select Yes, then select Ok and then select Finish

reboot for any change to make effect.