My Reachability Notifier is only able to be called once

Question

So, I have the following in my AppDelegate.
It will notify my when I turn my WIFI off but will not react after that initial run.
I have had this working in the past.

Answer 1

Try passing nil for the object parameter in addObserver. Also, for Swift 3, I had to initialize it with self.reachability = Reachability.forInternetConnection()

Answer 2

There are some changes in Reachability in Swift 3. Download the latest Reachability.swift file and add that in your project. Link

For Swift 2.x code please check my answer here

Swift 3.x code

Now in your AppDelegate take a Reachability class object

private var reachability:Reachability!

func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplicationLaunchOptionsKey: Any]?) -> Bool {
    // Override point for customization after application launch.

    //Network Reachability Notification check
    NotificationCenter.default.addObserver(self, selector: #selector(reachabilityChanged), name: ReachabilityChangedNotification, object: nil)

    self.reachability = Reachability.init()
    do {
        try self.reachability.startNotifier()
    } catch {
    }
    return true
}

reachabilityChanged method defination

//MARK:- Network Check
func reachabilityChanged(notification:Notification) {
    let reachability = notification.object as! Reachability
    if reachability.isReachable {
        if reachability.isReachableViaWiFi {
            print("Reachable via WiFi")
        } else {
            print("Reachable via Cellular")
        }
    } else {
         print("Network not reachable")
    }
}

This will be always called whenever user switches from Wifi to Cellular and vice versa or when Network Connects and Disconnects and vice versa.
Working fine in my case.

Read the documentation for more details in Swift 3 breaking changes section

Made a sample for you

https://www.dropbox.com/sh/bph33b12tyc7fpd/AAD2pGbgW3UnqgQoe7MGPpKPa?dl=0