Firebase Google login error

Question

This is the first time for me to try to use Firebase platform to develop android application

I am trying to login using google account but always I got an error

Here are the steps that I did

1. Create project on Firebase service.
2. Create project using Google developer console.
3. Connect two application together.
4. From authentication I enabled Google signin.
5. Adding sha1 and package name of my application in Firebase project
6. Also in the project console in Google developer console I create a new credential of type Android and add my app package name and sha1.
7. Download google-services.json file and add it to my app.

but still nothing worked for me. Can any one please revise my steps and let me know If I miss anything?

Error is:

Status{statusCode=unknown status code: 12501, resolution=null}