title: Invalid API Key supplied using Firebase
body: <p>I'm using Firebase Auth to allow users to sign up using Facebook. I have taken all the steps from here to implement sign up including adding <em>GoogleService-Info.plist</em> to my project. </p>
  
  <p>I get the Facebook permission screen all fine but when the app hits                     </p>
  
  <pre><code>FIRAuth.auth()?.signInWithCredential(credential) { (user, error) in
  </code></pre>
  
  <p>this error is returned: <strong>An invalid API Key was supplied in the request.</strong></p>
  
  <p>Can anyone help me with this please?</p>
  
  <p>Thanks</p>
  
  <p>Here is my function code to log in using Facebook.</p>
  
  <pre><code>@IBAction func signUpWithFacebook() {
  
      let fbLogin = FBSDKLoginManager()
  
      fbLogin.logInWithReadPermissions(["email"], fromViewController:self,  handler: {
          (result, error) -&gt; Void in
  
          if ((error) != nil) {
              print("Process error")
          } else if (result.isCancelled) {
              print("Cancelled");
          } else {
              print("Logged in");
  
              let accessToken = FBSDKAccessToken.currentAccessToken().tokenString
              let credential = FIRFacebookAuthProvider.credentialWithAccessToken(accessToken)
              print(FBSDKAccessToken.currentAccessToken().tokenString)
  
              FIRAuth.auth()?.signInWithCredential(credential) { (user, error) in
                  // ...
                  if let user = user{
                      print(user.displayName)
                  }
                  else{
  
                      if let error = error {
                          print(error.localizedDescription)
                      }
                  }
              }
  
          }
      })
  }
  </code></pre>