Invalid API Key supplied using Firebase
<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>