firebase_messaging/unknown: An unknown error has occured on Flutter IOS

This issue is caused by limited permission to your api key from Google cloud console, here are steps that fixed my issue,

1. Login to Google cloud console and select your current project

2. Select **API Credentials - APIs & Services ** or IAM Permissions on left sidebar.

3. Select iOS key(auto created by firebase)'s menu on right if you have selected **API Credentials - APIs & Services **

4. Select Edit API key

5. Under the Selected APIs: dropdown menu select these options: Firebase Installations API, Firebase Cloud Messaging API & FCM Registration API

Oh! my bad, I found the issue. My issue was a wrong api key of firebase in the GoogleServices-info.plist file

Thanks for all the support you gave me.

I resolved this issue by redownloading the GoogleService-Info.plist from the firebase & replace the current file.

in my case I have different bundle identifier on Xcode and in Firebase Console.

I have this issue after implementing Flavor on Flutter app. the Bundle Identifier is created dynamically based on the scheme on my Xcode

make sure you add push notification config in xcode

I have already faced this problem and searched a lot but did not find a solution.. But when I changed the emulator the problem was solved

Change the emulator

I was having the same issue on all of my IOS simulators, tried multiple things:

1. flutter clean
2. flutter pub get

but it didn't work.

The issue was with the FCM token for firebase push notifications. You wouldn't face this issue on any physical device , but if you have to work on the simulator than the solution that i figured was i commented out:

final fCMToken = await FirebaseMessaging.instance.getToken();

After this i stopped having the issue so i did all the work on the simulator and when i had to push out the build i enabled it again and it was working fine on the physical device.

In my case, i was using a different bundle id in debug and profile, and the key under APIs & Services => Credentials => iOS key (could be 2 keys, auto created by Firebase and auto created by Google Service) was set to iOS app restriction using the release bundle id, so, you need to add your debug bundle id here in the restrictions.

Emulators often encounter issues with receiving notifications, especially on iOS, as many emulators don't fully support this functionality.

Testing on a real device should resolve the problem.

I found a solution for the simulators in iOS:

https://github.com/firebase/flutterfire/issues/13575

"in iOS , use getAPNSToken instead of getToken and it will be work"

Make sure that your Flutter app targets iOS 8 or later. Please check this link below

https://firebase.google.com/docs/flutter/setup?platform=ios

in some android and ios devices not receiving firbase base responce because of its versions and api level

APns Was Null valeu And Problem with get Token When itry it in ios >12 It Work

  firebase_core: ^2.11.0 firebase_messaging: ^14.2.5 it support for me only the ios 13 and higher     <key>FirebaseAppDelegateProxyEnabled</key>
<true/> 
import UIKit
import Flutter
import Firebase
@main
@objc class AppDelegate: FlutterAppDelegate {
  override func application(
    _ application: UIApplication,
    didFinishLaunchingWithOptions launchOptions: [UIApplication.LaunchOptionsKey: Any]?
  ) -> Bool {
    GeneratedPluginRegistrant.register(with: self)
    //FirebaseApp.configure()
    return super.application(application, didFinishLaunchingWithOptions: launchOptions)
  }
}
# Uncomment this line to define a global platform for your project
platform :ios, '13.0'
swift_version = '5.0' 
# CocoaPods analytics sends network stats synchronously affecting flutter build latency.
ENV['COCOAPODS_DISABLE_STATS'] = 'true'

project 'Runner', {
  'Debug' => :debug,
  'Profile' => :release,
  'Release' => :release,
}

def flutter_root
  generated_xcode_build_settings_path = File.expand_path(File.join('..', 'Flutter', 'Generated.xcconfig'), __FILE__)
  unless File.exist?(generated_xcode_build_settings_path)
    raise "#{generated_xcode_build_settings_path} must exist. If you're running pod install manually, make sure flutter pub get is executed first"
  end

  File.foreach(generated_xcode_build_settings_path) do |line|
    matches = line.match(/FLUTTER_ROOT\=(.*)/)
    return matches[1].strip if matches
  end
  raise "FLUTTER_ROOT not found in #{generated_xcode_build_settings_path}. Try deleting Generated.xcconfig, then run flutter pub get"
end

require File.expand_path(File.join('packages', 'flutter_tools', 'bin', 'podhelper'), flutter_root)

flutter_ios_podfile_setup

target 'Runner' do
  use_frameworks!
  use_modular_headers!

  
  flutter_install_all_ios_pods File.dirname(File.realpath(__FILE__))
  target 'RunnerTests' do
    inherit! :search_paths
  end

post_install do |installer|
  installer.pods_project.targets.each do |target|
    flutter_additional_ios_build_settings(target)
    target.build_configurations.each do |config|
      config.build_settings['BUILD_LIBRARY_FOR_DISTRIBUTION'] = 'NO'
    end
  end
end

end
# target 'ImageNotification' do
#   use_frameworks!
#   pod 'Firebase/Messaging' , '~>10.7.0'
# end

The problem was not enabled the Push Notifications capability through XCode.

I had the same Problem

1. Upgrade your all firebase flutter packages in pubspec.yaml

• firebase_core
• firebase_crashlytics
• firebase_analytics
• firebase_messaging

2. flutter clean

• Remove pubspec.lock
• flutter pub get
• go to /iOS Directory
• remove /Pods Directory in your project
• remove Podfile.lock
• flutter run
• if that didn't work try 2 step again except flutter run and follow below steps
• • cd /ios
• • pod install or pod install --repo-update
• • flutter run

Turn out the error throw because I'm using a vpn app. Try to change your network to a different network then try again