It is not necessary to resort to factory reset your phone or your device, there are a range of things that you can do before you go to that step and we invite you to do so first.
Samsung Z2 Tizen Hard Reset
Switch off your cell phone.
Now press and hold Volume UP + Home button + Power button, and release them when Samsung logo appear.
Browse with volume buttons and select Phone initialization (Factory reset except SD card) and press power button
Select YES and press power button
Wait until the phone restarts.
Hard reset done