Apple Local Push Connectivity with error nil?

I would make sure that you are running this project on a development device with the debugger attached, and the console.app window filtering the logs from your app. That should tell you what is happening here.

From the container app, make sure that you are going through the path of:

1. loadAllFromPreferences to create the initial NEAppPushManager:

private var pushManager: NEAppPushManager?

...

NEAppPushManager.loadAllFromPreferences { managers, error in
    precondition(Thread.isMainThread)
    if let error = error {
        os_log("Error loading NEAppPushManager: %{public}@", error.localizedDescription)
        return
    }

    var manager: NEAppPushManager
    if let foundManager = managers?.first, NetworkManager.isOurManager(foundManager) {
        manager = foundManager
        os_log("Did find an existing NEAppPushManager, assigning the instance")
    } else {
        manager = NEAppPushManager()
        os_log("Did not find a NEAppPushManager, creating a new instance")
    }
    manager.delegate = self
    self.pushManager = manager
    
    // Setup Push Manager
    self.pushManager?.localizedDescription = ""
    self.pushManager?.providerBundleIdentifier = "com.my_team_name.my_app_name.PushProvider"
    self.pushManager?.isEnabled = true
    self.pushManager?.providerConfiguration = [
        "host": "hostinfo.com"
    ]
    self.pushManager?.matchSSIDs = ["NetworkSSID"]
    
}

1. Then load and save the NEAppPushManager:

guard let localManager = self.pushManager else {
    // Handle the failed unwrap
    return
}

localManager.loadFromPreferences { error in
    precondition(Thread.isMainThread)
    
    if let error = error {
        os_log("Error loading NEAppPushManager: %{public}@", error.localizedDescription)
        // Handle error
        return
    }
    
    localManager.saveToPreferences { error in
        if let nsError = error as NSError? {
            os_log("did not save configuration, error: %{public}@", nsError.localizedDescription)
            // Handle error
            return
        }
        os_log("Did Save Configuration Successfully")
        // Checkout logs here
    }
}

1. Configure the NEAppPushProvider with a constructor to see if it is even being reached after the saveToPreferences call.

class PushProvider: NEAppPushProvider {
   
    override init() {
        os_log("AppPushProvider init")
        super.init()
    }
    
    // MARK: - NEAppPushProvider Life Cycle
    

    override func start(completionHandler: @escaping (Error?) -> Void) {
        os_log("AppPushProvider start")
        
        completionHandler(error)
    }
    ...
}

Try this out and see where this gets you.

Matt Eaton
DTS Engineering, CoreOS
meaton3@apple.com

After a lot of trying I found that error

<NEAppPushManager: 0x281512160>: Failed to save the configuration: Error Domain=NEConfigurationErrorDomain Code=9 "configuration is unchanged" UserInfo={NSLocalizedDescription=configuration is unchanged}

it is what it means. When I change setting, error disappears. But PushProvider still not active. both function override init()  and 'override func start()' in PushProvider class was not executed at all.

When I change setting, error disappears. But PushProvider still not active. both function override init() and 'override func start()' in PushProvider class was not executed at all.

Right, it does sound like you have a configuration issue here if your can execute saveToPreferences without an error but the provider is not being hit at all.

Are there any other logs that may indicate what is happening in the Console.app? I would recommend deleting the app and network configuration entirely from your test device and then start over again. Then, reproduce the error while your device is recording logs to the console and see if that gives you any more clues as to what is happening.