This is Factory Reset Protection . It's a security feature. You must enter the previous Google account (email and password) that was used on the phone before the reset. If you don't know it, you cannot bypass this legally.
The phone will reboot and erase everything. This takes about 2-5 minutes. Use this method if you forgot your screen lock, password, or the phone is stuck on the logo screen. How to Hard Reset HUAWEI L21 P9 Lite
Open the Settings app.
If you have a screen lock (PIN, pattern, or password), enter it. This is Factory Reset Protection
Scroll down and tap Advanced Settings (on some EMUI versions, look for System ). look for System ).