Я очистил свой проект, чтобы устранить все ошибки. Кажется, приложение запускается и страница входа работает, но когда я попытался войти в Facebook, вот что происходит:

TCP_CONNECTION_EVENT_TLS_HANDSHAKE_COMPLETE in response to state ready and error (null)  
2016-09-15 12:36:50.254067 2[3083:89230] [] tcp_connection_event_notify 12 event: TCP_CONNECTION_EVENT_TLS_HANDSHAKE_COMPLETE, reason: nw_connection event, should deliver: true  
2016-09-15 12:36:50.254511 2[3083:89230] [] tcp_connection_get_statistics DNS: 3ms/7ms since start, TCP: 61ms/76ms since start, TLS: 99ms/172ms since start  
2016-09-15 12:36:50.492341 2[3083:89140] [] tcp_connection_cancel 12  
2016-09-15 12:36:50.493012 2[3083:88773] [] nw_socket_handle_socket_event Event mask: 0x4  
2016-09-15 12:36:50.493506 2[3083:88773] [] nw_socket_handle_socket_event Socket received WRITE_CLOSE event  
2016-09-15 12:36:50.494087 2[3083:88773] [] nw_endpoint_handler_cancel [12 graph.facebook.com:443 ready resolver (satisfied)]  
2016-09-15 12:36:50.494691 2[3083:88773] [] nw_endpoint_handler_cancel [12.1 31.13.78.13:443 ready socket-flow (satisfied)]  
2016-09-15 12:36:50.495482 2[3083:88773] [] __nw_socket_service_writes_block_invoke sendmsg(fd 15, 31 bytes): socket has been closed  
2016-09-15 12:36:50.495878 2[3083:88773] [] nw_endpoint_flow_protocol_error [12.1 31.13.78.13:443 cancelled socket-flow (null)] Socket protocol sent error: [32] Broken pipe  
2016-09-15 12:36:50.496536 2[3083:88773] [] nw_endpoint_flow_protocol_disconnected [12.1 31.13.78.13:443 cancelled socket-flow (null)] Output protocol disconnected  
2016-09-15 12:36:50.496888 2[3083:88773] [] nw_resolver_cancel_on_queue 0x6000003042f0  
2016-09-15 12:36:50.497285 2[3083:88773] [] -[NWConcrete_tcp_connection dealloc] 12

Это всего лишь фрагмент файла журнала вывода, когда я пытался войти в систему.

Кстати, мой код настроен как таковой для loginviewcontroller

import UIKit
import FBSDKLoginKit
import Firebase
import FirebaseAuth

class FacebookLoginViewController: UIViewController, FBSDKLoginButtonDelegate{

    var loginButton: FBSDKLoginButton = FBSDKLoginButton()

    override func viewDidLoad() {
        super.viewDidLoad()
        // Do any additional setup after loading the view, typically from a nib.
        self.loginButton.center = self.view.center
        self.loginButton.readPermissions = ["public_profile", "email", "user_friends"]
        self.view!.addSubview(loginButton)
        self.loginButton.delegate = self


        FIRAuth.auth()?.addAuthStateDidChangeListener { auth, user in
            if let user = user {
                // User is signed in.
                self.performSegueWithIdentifier("loggedIn", sender: self)

            }
        }

    }

    override func didReceiveMemoryWarning() {
        super.didReceiveMemoryWarning()
        // Dispose of any resources that can be recreated.
    }


    func loginButton(loginButton: FBSDKLoginButton!, didCompleteWithResult result: FBSDKLoginManagerLoginResult!, error: NSError!) {
        print("user logged in")



        if(error != nil)
        {
        }

        else if(result.isCancelled){

        }

        else{
        // Exchange facebook credential for a firebase credential

        let credential = FIRFacebookAuthProvider.credentialWithAccessToken(FBSDKAccessToken.currentAccessToken().tokenString)

        // Login to firebase
        FIRAuth.auth()?.signInWithCredential(credential) { (user, error) in

            self.performSegueWithIdentifier("loggedIn", sender: self)
            print("user logged in to firebase")
            }
        }

    }

    func loginButtonDidLogOut(loginButton: FBSDKLoginButton!) {
        print("user logged out")
    }

}

вот didFinishLaunchingWithOptions

func application(application: UIApplication, didFinishLaunchingWithOptions launchOptions: [NSObject: AnyObject]?) -> Bool {
        FIRApp.configure()
        // Override point for customization after application launch.
        let navAppearance = UINavigationBar.appearance()
        let tabAppearance = UITabBar.appearance()

        let backImage = UIImage(named: "back")
        navAppearance.backIndicatorImage = backImage
        navAppearance.backIndicatorTransitionMaskImage = backImage


        let lightBlackColour = UIColor(red: 50/255.0, green: 50/255.0, blue: 54/255.0, alpha: 1.0)
        let lightYellowColour = UIColor(red: 255/255.0, green: 250/255.0, blue: 36/255.0, alpha: 1.0)

        navAppearance.tintColor = lightYellowColour
        navAppearance.barTintColor = lightBlackColour // Set the bar tint colour
        navAppearance.titleTextAttributes = [NSForegroundColorAttributeName: lightYellowColour]

        tabAppearance.barTintColor = lightBlackColour
        tabAppearance.tintColor = lightYellowColour

        let barButtonAppearance = UIBarButtonItem.appearance()
        barButtonAppearance.setBackButtonTitlePositionAdjustment(UIOffsetMake(0, -60), forBarMetrics: .Default)
        barButtonAppearance.setBackButtonTitlePositionAdjustment(UIOffsetMake(0, -60), forBarMetrics: .Compact)

        UIApplication.sharedApplication().statusBarStyle = .LightContent

        FBSDKApplicationDelegate.sharedInstance().application(application, didFinishLaunchingWithOptions: launchOptions)
        return true
    }