title: I don't know where the internal error is occurring.It says that the API key is not valid and that I need to pass a valid API key
body: <pre><code>import 'package:firebase_auth/firebase_auth.dart';
  import 'package:flutter/material.dart';
  import 'package:time_trackerpractice/app/sign_in/sign_in_button.dart';
  import 'package:time_trackerpractice/app/sign_in/social_sign_in_button.dart';
  import 'package:time_trackerpractice/common_widgets/custom_raised_button.dart';
  import 'package:time_trackerpractice/services/auth.dart';
  
  class SignInPage extends StatelessWidget {
    const SignInPage({Key key,@required this.auth, @required this.onSignIn}) : super(key: key);
    final AuthBase auth;
    final void Function(User) onSignIn;
  
  
  Future&lt;void&gt; _signInAnonymously() async{
    try {
      final user = await auth.signInAnonymously();
     onSignIn(user);
    }catch(e){
      print(e.toString());
    }
  }
    @override
    Widget build(BuildContext context) {
      return Scaffold(
          appBar: AppBar(
            title: Text('Time Tracker'),
            elevation: 20.0,
          ),
          body: _buildContent(),
        backgroundColor: Colors.grey[200],
      );
    }
  
    Widget _buildContent() {
      return Padding(
          padding:EdgeInsets.all(16.0),
          child: Column(
            mainAxisAlignment: MainAxisAlignment.center ,
            crossAxisAlignment: CrossAxisAlignment.stretch,
            children: &lt;Widget&gt;[
              Text(
                'Sign in',
                textAlign:TextAlign.center,
                style: TextStyle(
                  fontSize: 32.0,
                  fontWeight: FontWeight.w600,
                ),
              ),
  
                SizedBox(height: 48.0),
                SocialSignInButton(
                  assetName: 'images/google-logo.png',
                  text: 'Sign in with Google',
                  textColor: Colors.black87,
                  color:Colors.white,
                  onPressed: (){},
                ),
              SizedBox(height:8.0),
              SocialSignInButton(
                assetName: 'images/facebook-logo.png',
                text:'Sign in with Facebook',
                textColor: Colors.white,
                color: Color(0xFF334D92),
                onPressed:() {},
              ),
              SizedBox(height: 8.0),
            SignInButton(
              text: 'Sign in with email',
              textColor: Colors.white,
              color: Colors.teal[700],
              onPressed: () {},
            ),
              SizedBox(height: 8.0),
              Text(
                'or',
                style: TextStyle( fontSize: 14.0, color: Colors.black87),
                textAlign:TextAlign.center,
              ),
              SizedBox(height: 8.0),
              SignInButton(
                text: 'Go anonymous',
                textColor: Colors.black,
                color: Colors.lime[300],
                onPressed: _signInAnonymously,
              ),
            ],
          ),
        );
    }
  }
  </code></pre>
  <p>I am working on a flutter course on udemy.I am trying to sign in to the go anonymous button,but I keep getting this error that the API key isn't valid but I triple check everything and I still don't know were I went wrong.I was wondering where the internal errors occurring.And how can I make the API key valid.After I made the API valid how can I pass the API key so I can log in to the go anonymous button.</p>