If the phone is still unable to boot to the Home screen, you may need to reset the phone to factory settings. Since the phone will not boot properly, the factory reset can only be performed using special commands outside of the device settings. See
How do I perform a factory reset using hardware buttons? for details.
In phones with
Android 5 or higher, Device Protection may be enabled, which means that after the factory reset, you'll need to sign in using the same
Google Account that was logged into your phone. If you forgot your
Google Account password, use your computer web browser and go to
www.google.com/accounts/recovery to reset your password first.
To perform the factory reset:
For some phones, you may need to hold VOLUME UP instead.