Firebase Auth using phone number returns an internal error

Question

I set up my app to be able to send Apple Notifications using firebase and I verified that it works using the console. Now I want to do phone authentication which is built on top of APN.

So I wrote this:

PhoneAuthProvider.provider().verifyPhoneNumber(phoneNumber) { verificationID, error in
  if error != nil {
    print("Verification code not sent \(error!)")
  } else {
    print ("Successful.")
  }

And I get:

Error Domain=FIRAuthErrorDomain Code=17999 "An internal error has occurred, print and inspect the error details for more information." UserInfo={NSUnderlyingError=0x170046db0 {Error Domain=FIRAuthInternalErrorDomain Code=3 "(null)" UserInfo={FIRAuthErrorUserInfoDeserializedResponseKey={
    code = 500;
    message = "<null>";
}}}, error_name=ERROR_INTERNAL_ERROR, NSLocalizedDescription=An internal error has occurred, print and inspect the error details for more information.}

Any idea? Should I file a bug against firebase?

I am using iOS SDK 4.0.0 (latest zip I could find.)

UPDATE:

I disabled method swizzling by adding FirebaseAppDelegateProxyEnabled to info.plist and set it to NO

func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {
    // Pass device token to auth.
    Auth.auth().setAPNSToken(deviceToken, type: .prod)
}

Answer 1

Tested with latest Firebase iOS SDK i.e. 4.0.0 and Xcode 8.3

Firstly , remove this key FirebaseAppDelegateProxyEnabled from info.plist. This is not needed.

Now in AppDelegate.swift add following functions

import Firebase
import UserNotifications

@UIApplicationMain

class AppDelegate: UIResponder, UIApplicationDelegate , UNUserNotificationCenterDelegate{
    var window: UIWindow?
    func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {

        if #available(iOS 10.0, *) {
            // For iOS 10 display notification (sent via APNS)
            UNUserNotificationCenter.current().delegate = self
            let authOptions: UNAuthorizationOptions = [.alert, .badge, .sound]
            UNUserNotificationCenter.current().requestAuthorization(
                options: authOptions,
                completionHandler: {_, _ in })
        } else {
            let settings: UIUserNotificationSettings =
                UIUserNotificationSettings(types: [.alert, .badge, .sound], categories: nil)
            application.registerUserNotificationSettings(settings)
        }

        application.registerForRemoteNotifications()
        FirebaseApp.configure()
        return true
    }
func application(_ application: UIApplication, didRegisterForRemoteNotificationsWithDeviceToken deviceToken: Data) {
    // Pass device token to auth.
    let firebaseAuth = Auth.auth()

    //At development time we use .sandbox
    firebaseAuth.setAPNSToken(deviceToken, type: AuthAPNSTokenType.sandbox)

    //At time of production it will be set to .prod
}

func application(_ application: UIApplication, didReceiveRemoteNotification userInfo: [AnyHashable : Any], fetchCompletionHandler completionHandler: @escaping (UIBackgroundFetchResult) -> Void) {
    let firebaseAuth = Auth.auth()

    if (firebaseAuth.canHandleNotification(userInfo)){
        print(userInfo)
        return
    }
}*

Send a verification code to the user's phone:

In the class where you want to integrate Phone Authentication write :

Note : I have added +91 as its country code for India. You can add country code according to your region.

 PhoneAuthProvider.provider().verifyPhoneNumber("+919876543210") { (verificationID, error) in
       if ((error) != nil) {
             // Verification code not sent.
             print(error)
       } else {
              // Successful. User gets verification code 
              // Save verificationID in UserDefaults
             UserDefaults.standard.set(verificationID, forKey: "firebase_verification")
             UserDefaults.standard.synchronize()
             //And show the Screen to enter the Code.
       }               

Sign in the user with the verification code:

 let verificationID = UserDefaults.standard.value(forKey: "firebase_verification")
 let credential = PhoneAuthProvider.provider().credential(withVerificationID: verificationID! as! String, verificationCode: self.txtEmailID.text!)

   Auth.auth().signIn(with: credential, completion: {(_ user: User, _ error: Error?) -> Void in
         if error != nil {
            // Error
          }else {
             print("Phone number: \(user.phoneNumber)")
              var userInfo: Any? = user.providerData[0]
                    print(userInfo)
                }
         } as! AuthResultCallback)

Answer 2

In my case it was the apns token type that was wrong:

Auth.auth().setAPNSToken(deviceToken, type: AuthAPNSTokenType.prod)

should have been:

Auth.auth().setAPNSToken(deviceToken, type: AuthAPNSTokenType.sandbox)