I factory reset my cell phone and now it won't work .

[AC Question]

I reset my phone a few nights ago and i can't use it AT ALL. When my LGK7 is turned on it confirms that the google name and password are correct but my phone says "sign in with a google account that was previously synced on this device" I am so frustrated and confused. I'm able to log onto my computer and my iphone with the same google name and password. I just want my cell phone to work again!! Please help me. Thanks!