Well this another problem in android phone. Why does it appear? Based on the survey mostly due to they forgot SIM or PIN password of their phone. I never encounter this problem but I will teach you how to fix it based in my friend experiences and also an android developer who shared his knowledge on how easy to fix privacy protection password. Actually there’s no other way to fix it and it not easy to fix because it access your root system even in factory settings or hard reset . The only method is flash the original firmware or stock rom via SPFT. This method already discuss just follow my tutorial on how to flash via SPFT here. You need to find working stock rom or download in my stock rom section if not available you can post your request here.