Xcode – flutter build ipa – Command PhaseScriptExecution failed with a nonzero exit code

I am using flutter and trying to build an ipa file, I am able to run my app my device or simulator no problem, but can’t build an ipa file. I am using the flutter command flutter build ipa and I get this error:

Command PhaseScriptExecution failed with a nonzero exit code

I have tried to do the following:

flutter clean
flutter pub get
cd ios
pod install
pod update

Here is my Podfile:

platform :ios, '11.0'

# 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__))
  pod 'DKImagePickerController/PhotoGallery', :git => 'https://github.com/miguelpruivo/DKImagePickerController.git'
end

post_install do |installer|
  installer.pods_project.targets.each do |target|
    flutter_additional_ios_build_settings(target)
  end
end

And here is my pubspec.yaml file:

name: myApp
description: An app for parents built by parents

version: 1.0.0+1

environment:
  sdk: ">=2.15.1 <3.0.0"

dependencies:
  flutter:
    sdk: flutter

  firebase_core: 1.12.0
  firebase_auth: 3.3.6
  cloud_firestore: 3.1.7
  firebase_messaging: 11.2.6
  firebase_database: 9.0.6
  firebase_storage: 10.2.6

  shared_preferences: 2.0.12
  json_annotation: 4.4.0
  uuid: 3.0.5
  flutter_easyloading: 3.0.3
  flutter_svg: 1.0.3
  adaptive_dialog: 1.3.0
  image_picker: 0.8.4+5
  charts_flutter: 0.12.0
  url_launcher: 6.0.12
  dart_date: 1.1.1
  carousel_slider: 4.0.0
  dots_indicator: 2.1.0
  open_mail_app: 0.4.4
  percent_indicator: 4.0.0
  audioplayers: 0.20.1
  number_picker_dialog: 0.0.1
  share_plus: 3.1.0
  flutter_tabler_icons: 1.1.1
  flutter_local_notifications: 9.4.0
  intl: 0.17.0

dev_dependencies:
  flutter_test:
    sdk: flutter

  flutter_lints: 1.0.0
  build_runner: 2.1.7
  json_serializable: 6.1.4

flutter_icons:
  android: "launcher_icon"
  ios: true
  remove_alpha_ios: true
  image_path: "assets/icons/logo.png"

flutter_launcher_name:
  name: "MyApp"

flutter:
  uses-material-design: true

  assets:
    - assets/images/intro/
    - assets/images/questions/
    - assets/images/badges/
    - assets/icons/
    - assets/data/
    - assets/audio/

  fonts:
    - family: Chalkboard
      fonts:
        - asset: assets/fonts/chalkboard/Daneehand Demo.otf
    - family: Poppins-Light
      fonts:
        - asset: assets/fonts/poppins/Poppins-Light.ttf
    - family: Poppins-Regular
      fonts:
        - asset: assets/fonts/poppins/Poppins-Regular.ttf
    - family: Poppins-Medium
      fonts:
        - asset: assets/fonts/poppins/Poppins-Medium.ttf
    - family: Poppins-SemiBold
      fonts:
        - asset: assets/fonts/poppins/Poppins-SemiBold.ttf
    - family: Poppins-Bold
      fonts:
        - asset: assets/fonts/poppins/Poppins-Bold.ttf

Can anyone tell me what I am doing wrong?