title: Facebook login for iOS error: The operation couldn’t be completed. (com.facebook.sdk.core error 3.)
body: <p>I'm receiving the error code:</p>
  
  <pre><code>The operation couldn’t be completed. (com.facebook.sdk.core error 3.)
  </code></pre>
  
  <p>for logging into facebook on my app and am not sure why.  Here is my viewController code:</p>
  
  <pre><code>import FBSDKCoreKit
  import FBSDKLoginKit
  
  @IBOutlet weak var facebookLoginButton: FBSDKLoginButton!
  
  
    override func viewDidLoad() {
      super.viewDidLoad()
  
    facebookLoginButton.readPermissions = ["public_profile", "email", "user_friends"]
      facebookLoginButton.delegate = self
  
    }
  
    //MARK: Facebook Login
  
    func loginButton(loginButton: FBSDKLoginButton!, didCompleteWithResult result: FBSDKLoginManagerLoginResult!, error: NSError!) {
      if error == nil {
  
        print("Login Complete")
  
        performSegueWithIdentifier("facebookSegue", sender: self)
  
      } else {
  
        print(error.localizedDescription)
  
      }
    }
  
    func loginButtonDidLogOut(loginButton: FBSDKLoginButton!) {
      print("User logged out")
    }
  </code></pre>
  
  <p>Here is the appDelegate:</p>
  
  <pre><code>import FBSDKCoreKit
  
      func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -&gt; Bool {
          // Override point for customization after application launch.
  
        //Facebook login
          return FBSDKApplicationDelegate.sharedInstance().application(application, didFinishLaunchingWithOptions: launchOptions)
      }
  
    func application(application: UIApplication, openURL url: NSURL, sourceApplication: String?, annotation: AnyObject) -&gt; Bool {
  
      //Facebook login
      return FBSDKApplicationDelegate.sharedInstance().application(application, openURL: url, sourceApplication: sourceApplication, annotation: annotation)
    }
  </code></pre>
  
  <p>I think the code is correct but maybe I'm missing something, any help is appreciated!</p>