ArgumentError after changed config.currency in /admin/products/ in Solidus 3.0

I'm new in ruby on rails and Solidus. I created my project by following this guide: https://guides.solidus.io/developers/getting-started/first-time-installation.html

Then, I want to change my default currency from "USD" to "AUD" in config/initializers/spree.rb
( config.currency = "AUD" )

Then, when I go to http://localhost:3000/admin/products. It shows (* other pages work normal)

Please help.(Tried restart server but same)

Ruby version: ruby '3.0.2'
Solidus version: "solidus", "~> 3.0"
Rails 6.1.4.1

spree.rb

# Configure Solidus Preferences
# See http://docs.solidus.io/Spree/AppConfiguration.html for details

Spree.config do |config|
  # Core:

  # Default currency for new sites
  config.currency = "AUD"

  # from address for transactional emails
  config.mails_from = "store@example.com"

  # Uncomment to stop tracking inventory levels in the application
  # config.track_inventory_levels = false

  # When set, product caches are only invalidated when they fall below or rise
  # above the inventory_cache_threshold that is set. Default is to invalidate cache on
  # any inventory changes.
  # config.inventory_cache_threshold = 3

  # Configure adapter for attachments on products and taxons (use ActiveStorageAttachment or PaperclipAttachment)
  config.image_attachment_module = 'Spree::Image::ActiveStorageAttachment'
  config.taxon_attachment_module = 'Spree::Taxon::ActiveStorageAttachment'

  # Defaults
  # Permission Sets:

  # Uncomment and customize the following line to add custom permission sets
  # to a custom users role:
  # config.roles.assign_permissions :role_name, ['Spree::PermissionSets::CustomPermissionSet']


  # Frontend:

  # Custom logo for the frontend
  # config.logo = "logo/solidus.svg"

  # Template to use when rendering layout
  # config.layout = "spree/layouts/spree_application"


  # Admin:

  # Custom logo for the admin
  # config.admin_interface_logo = "logo/solidus.svg"

  # Gateway credentials can be configured statically here and referenced from
  # the admin. They can also be fully configured from the admin.
  #
  # Please note that you need to use the solidus_stripe gem to have
  # Stripe working: https://github.com/solidusio-contrib/solidus_stripe
  #
  # config.static_model_preferences.add(
  #   Spree::PaymentMethod::StripeCreditCard,
  #   'stripe_env_credentials',
  #   secret_key: ENV['STRIPE_SECRET_KEY'],
  #   publishable_key: ENV['STRIPE_PUBLISHABLE_KEY'],
  #   server: Rails.env.production? ? 'production' : 'test',
  #   test_mode: !Rails.env.production?
  # )
end

Spree::Frontend::Config.configure do |config|
  config.locale = 'en'
end

Spree::Backend::Config.configure do |config|
  config.locale = 'en'

  # Uncomment and change the following configuration if you want to add
  # a new menu item:
  #
  # config.menu_items << config.class::MenuItem.new(
  #   [:section],
  #   'icon-name',
  #   url: 'https://solidus.io/'
  # )
end

Spree::Api::Config.configure do |config|
  config.requires_authentication = true
end

Spree.user_class = "Spree::LegacyUser"

# Rules for avoiding to store the current path into session for redirects
# When at least one rule is matched, the request path will not be stored
# in session.
# You can add your custom rules by uncommenting this line and changing
# the class name:
#
# Spree::UserLastUrlStorer.rules << 'Spree::UserLastUrlStorer::Rules::AuthenticationRule'

Gemfile

source 'https://rubygems.org'
git_source(:github) { |repo| "https://github.com/#{repo}.git" }

ruby '3.0.2'

# Bundle edge Rails instead: gem 'rails', github: 'rails/rails', branch: 'main'
gem 'rails', '~> 6.1.4', '>= 6.1.4.1'
# Use sqlite3 as the database for Active Record
gem 'sqlite3', '~> 1.4'
# Use Puma as the app server
gem 'puma', '~> 5.0'
# Use SCSS for stylesheets
gem 'sass-rails', '>= 6'
# Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
gem 'jbuilder', '~> 2.7'
# Use Redis adapter to run Action Cable in production
# gem 'redis', '~> 4.0'
# Use Active Model has_secure_password
# gem 'bcrypt', '~> 3.1.7'

# Use Active Storage variant
# gem 'image_processing', '~> 1.2'

# Reduces boot times through caching; required in config/boot.rb
gem 'bootsnap', require: false

group :development, :test do
  # Call 'byebug' anywhere in the code to stop execution and get a debugger console
  gem 'byebug', platforms: [:mri, :mingw, :x64_mingw]
end

group :development do
  # Access an interactive console on exception pages or by calling 'console' anywhere in the code.
  gem 'web-console', '>= 4.1.0'
  # Display performance information such as SQL time and flame graphs for each request in your browser.
  # Can be configured to work on production as well see: https://github.com/MiniProfiler/rack-mini-profiler/blob/master/README.md
  gem 'rack-mini-profiler', '~> 2.0'
  gem 'listen', '~> 3.3'
  # Spring speeds up development by keeping your application running in the background. Read more: https://github.com/rails/spring
  gem 'spring'
end

group :test do
  # Adds support for Capybara system testing and selenium driver
  gem 'capybara', '>= 3.26'
  gem 'selenium-webdriver'
  # Easy installation and use of web drivers to run system tests with browsers
  gem 'webdrivers'
end

# Windows does not include zoneinfo files, so bundle the tzinfo-data gem
gem 'tzinfo-data', platforms: [:mingw, :mswin, :x64_mingw, :jruby]

gem "solidus", "~> 3.0"
gem 'solidus_auth_devise'

BigDecimal raises ArgumentError if you supply an empty String.

require 'bigdecimal'

BigDecimal('')
#=> ArgumentError (invalid value for BigDecimal(): "")

BigDecimal('0')
#=> 0.0

You could for example ensure that all your products has a default value of 0. You can achieve this by editing your migration:

t.integer :value, default: 0