How can I fix Unfortunately, the process com.android.phone has stopped?

[AC Question]

Unfortunately, the process com.android.phone has stopped

How to fix this. I've tried all the info I gathered from Google but still not working on my LG G PRO 2

 

[B. Diddy]

Re: Unfortunately, the process com.android.phone has stopped

Welcome to Android Central! Try booting into Safe Mode, which temporarily disables all 3rd party apps. On most Android devices, while powered on, press and hold Power until the Power Off menu appears. Press and hold the Power Off selection until the Safe Mode prompt appears. Tap OK.

If the problem disappears in Safe Mode, then something you installed is causing the problem. You may have to uninstall apps one by one until the problem disappears. If the problem persists in Safe Mode, then it's more likely to be a hardware or firmware problem.