Before Android 5.0 (Lollipop), doing a factory reset on your Android phone would restore it to its original state like it was brand new. From Lollipop, doing a factory reset in recovery (when the device is still associated with a Google account) still requires that you supply the credentials of the Google account associated with the device before the factory reset was done. This is called Factory Reset Protection (FRP), a security / anti-theft feature.
If you find yourself locked out of your phone after a factory reset then this guide will come in handy.
How to remove / bypass Factory Reset Protection (FRP) on an MTK phone
Method 1: Setup selection
During setup (using the setup wizard), do not connect to a Wi-Fi network. Also, untick "Protect this device"
Method 2: Format FRP Partition Using SP Flash tool
Using the guide @ https://forum.hovatek.com/thread-21638.html , format ONLY FRP partition
Method 3: Miracle Box method
Follow the method @ https://forum.hovatek.com/thread-13335.html ; In step 5, select Clear Settings/Frp
How do I avoid the stress of factory reset protection when I need to do a factory reset
Navigate to Settings > Accounts and delete / sign out of the Google account associated with the device