GoogleSignInClient return 8 (internal error)

Question

I'm trying to connect my game to Google Play Games Services, but when I try to login, it always returns me an error code 8 (internal error).
The code is copy pasted from Google example:

lateinit var signInClient: GoogleSignInClient

override fun onCreate(savedInstanceState: Bundle?) {
    super.onCreate(savedInstanceState)
    setContentView(R.layout.layout_settings)
    settings_login.setOnClickListener { login() }
    signInClient = GoogleSignIn.getClient(this,
            GoogleSignInOptions.Builder(GoogleSignInOptions.DEFAULT_GAMES_SIGN_IN).build()
    )
}

private fun login() {
    startActivityForResult(signInClient.signInIntent, 9001)
}

override fun onActivityResult(requestCode: Int, resultCode: Int, data: Intent?) {
    super.onActivityResult(requestCode, resultCode, data)
    if (requestCode != 9001) {
        return
    }

    val task = GoogleSignIn.getSignedInAccountFromIntent(intent)

    try {
        val account = task.getResult(ApiException::class.java)
        onConnected(account)
    } catch (apiException: ApiException) {
        var message: String? = apiException.message
        if (message == null || message.isEmpty()) {
            message = getString(R.string.signin_other_error)
        }

        onDisconnected()

        AlertDialog.Builder(this)
                .setMessage(message)
                .setNeutralButton(android.R.string.ok, null)
                .show()
    }
}

In Google Play Console I've linked my game with debug keystore SHA-1. I've checked everythin mentioned in Troubleshooting guide, but I still get this message again and again.
Does someone faced this issue? Any ideas how to debug it?
EDIT:
I found that it actually logs me in - if I restart game, method signInSilently() will be successful. However, it still shows this error 8 when I logout and try to log in manually. Could it be the problem with login activity overlay?
Oh, and I checked api access in Google Play Api Console - it shows that api actually receives my calls and it doesn't mention any errors.
EDIT 2: I've added requestEmail() to GoogleSignInOptions.Builder, and it shows me overlay with access request. However, it still fails in GoogleSignIn.getSignedInAccountFromIntent(intent).getResult(ApiException::class.java) with same error (8 - internal error).

Answer 1

It looks like this bug in Google Play Services 12.2.21:

https://github.com/googlesamples/google-services/issues/358

Google is supposed to be working on a fix for release over the air soon..