Unhandled Exception: PlatformException(channel-error, Unable to establish connection on channel., null, null)

I spent a long time looking into this and eventually traced it to the plugin registrar being nil when setting up the plugin.

This was caused by setting my iOS app root view controller to anything other than FlutterViewController (i.e. in my case, I had a UINavigationController as the root). This will result in a failure to register all your plugins.

The app delegate assumes that the root view controller is a FlutterViewController, so if it isn't then you will need to re-direct all plugin-related function calls to your FlutterViewController from your app delegate.

You can do this by overriding these functions as follows in AppDelegate.swift:

@UIApplicationMain
@objc class AppDelegate: FlutterAppDelegate {

    var flutterViewController: FlutterViewController!

    override func application(_ application: UIApplication, didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?) -> Bool {

        // Wherever your FlutterViewController is in your view hierarchy, you need to get a reference to it:
        let navController = window!.rootViewController as! UINavigationController
        self.flutterViewController = navController.children.first as! FlutterViewController

        GeneratedPluginRegistrant.register(with: self)
        return super.application(application, didFinishLaunchingWithOptions: launchOptions)
    }

    // Add these overrides to redirect all the FlutterAppDelegate functions to your flutterViewController:

    override func registrar(forPlugin pluginKey: String) -> FlutterPluginRegistrar? {
        flutterViewController.registrar(forPlugin: pluginKey)
    }

    override func hasPlugin(_ pluginKey: String) -> Bool {
        flutterViewController.hasPlugin(pluginKey)
    }

    override func valuePublished(byPlugin pluginKey: String) -> NSObject? {
        flutterViewController.valuePublished(byPlugin: pluginKey)
    }

}

I had the same issue and stumped on this post.

In my case I was able to detect which plugin was in fact giving the error and it turned out to be firebase_core. So, I decided to upgrade the package to the latest version which happened to be 1.21.1 in my case.

So, to solve the issue I will suggest you try changing the version of the firebase_core package you're using to the latest in the pubspec.yaml file of your project like so:

firebase_core: ^1.21.1 (replace with latest verison)

Or you can just run:

flutter pub upgrade firebase_core

This will upgrade firebase_core to the latest version.

Or you can as well put any as the version code in the pubspec.yaml file of your project like so:

firebase_core: any (upgrades firebase_core to the latest verison)

Running flutter clean and flutter pub get worked for me.

In my case, This line was missing in MainAcitivty.java

GeneratedPluginRegistrant.registerWith(flutterEngine);

with it's import

import io.flutter.plugins.GeneratedPluginRegistrant;

As of 9th July, 2025. I updated my Dart environment.

environment:
  sdk: ^3.8.1

Then I also updated all firebase dependencies to the latest version.

  dependencies:
  firebase_analytics: ^11.5.2
  firebase_app_check: ^0.3.2+9
  firebase_auth: ^5.6.2
  firebase_core: ^3.15.1
  firebase_crashlytics: ^4.3.9
  firebase_messaging: ^15.2.9
  firebase_performance: ^0.10.1+9
  firebase_storage: ^12.4.9
  firebase_ui_firestore: ^1.7.2 

  dev dependencies:
  firebase_auth_platform_interface: ^7.7.2 
  firebase_core_platform_interface: ^6.0.0

After that, I run:
flutter clean
flutter pub get

And that resolved the issue.

I was facing the same issue, After 1 day of trying, I realized that the variable I was passing to createUserWithEmailAndPassword() had no value. This function was working totally fine when I was passing hardcoded value i.e. email & password

Please also check the compileSdkVersion in android/app/build.gradle and update it to 33

If you are using these dependecies then replace it with a latest version:

• firebase_messaging
• firebase_core
• flutter_local_notifications

Then in android/app/build.gradle update compileSdkVersion flutter.compileSdkVersion to 33

I also effected from that issue for few hours, finally I found issue that was I ran my emulator as windows (:, yeah please run with Android emulator you selected vm.

In my case i was trying to use "google_mobile_ads" and "admob_flutter" at the same time. You must choose one only.

Try out different devices like Chrome or Android if you run into this error. Note that firebase does not run on all platforms flutter runs on.

In my case I was developing on Linux and got that PlatformException because I was launching the app as a Linux program - which is not supported by Firebase and thus raises the error even though everything is configured correctly.

for me only flutter pub cache clean helped with the issue

Adding GeneratedPluginRegistrant.registerWith(flutterEngine); to MainActivity.kt did work for me.

import io.flutter.plugins.GeneratedPluginRegistrant

//...

override fun configureFlutterEngine(flutterEngine: FlutterEngine) {
   super.configureFlutterEngine(flutterEngine)
   GeneratedPluginRegistrant.registerWith(flutterEngine);
   configureChannels(flutterEngine)
}

Sousce:
https://github.com/firebase/flutterfire/issues/9113#issuecomment-1188429009

I was have this problem. after downgrade awesome_notifications package to 0.6.21, resolved this.

I had same problem with webview_flutter package , after longtime and more search found this package has confilic with one another packages in may case it was "wear" package , after delete that its worked

Posting on 19 March 2025.

first I would suggest to upgrade the flutter firebase packages (including firebase_core, firebase_auth) .

flutter pub outdated

flutter pub upgrade outdated_package

project > app > build.gradle [update compileSdk, minSdk ]

android {
    namespace = "com.example.pixelplayapp" //your app namespace
    compileSdk = 35
    ndkVersion = 30

    compileOptions {
        sourceCompatibility = JavaVersion.VERSION_1_8
        targetCompatibility = JavaVersion.VERSION_1_8
    }
    // if youre using gradle 8.1.1-8.3.4
     dependencies {
        coreLibraryDesugaring 'com.android.tools:desugar_jdk_libs:2.0.3' 
    }

    kotlinOptions {
        jvmTarget = JavaVersion.VERSION_1_8
    }

    defaultConfig {
        // TODO: Specify your own unique Application ID (https://developer.android.com/studio/build/application-id.html).
        applicationId = "com.example.pixelplayapp"
        // You can update the following values to match your application needs.
        // For more information, see: https://flutter.dev/to/review-gradle-config.
        minSdk = 23
        targetSdk = flutter.targetSdkVersion
        versionCode = flutter.versionCode
        versionName = flutter.versionName
    }

flutter clean

flutter pub get

flutter run. By doing so I have fixed my issue.