Did a factory reset by accident and now can't get past the sign into to verify with last google account synced to device.
The account is a link between your device and Google,
You need to log into the Google account associated with your device...
If you used the Create New Account option while setting up your device, you'll need this account details.
However if you selected Log In ( I already have an account ) and used a current Google account, you'll need its details.
The password is not device specific, it is your Google account password, so if you are having issues remembering the password.
Open a google service on your computer ( YouTube, Gmail, etc.. )
Select forgotten password
Follow the steps to recover your account
Change your password ( the final step )
Use the new password to log in.
If you are unsure on the account you used when setting your device up, you'll need to go through all your accounts and try to recover each one, until you get the correct account.