Nvidia Geforce 210 in Sierra

Check Graphics Enabler in Clover Configurator.

Nope Facetime is in not effected in any why by your video card. Facetime will work if it´s correctly registered with Apple regardless whether you got HardwareAccelerated Video or not. Your Problem is still in the registration and activation Process with Apple. Even tough you can successfully login to Facetime it does not mean that your Account will work with Facetime. If your account is not fully activated on Apples Servers you´ll might be able to login but you´ll not be able to add contacts or send or receive FaceTime calls...