NoMethodError: undefined method `[]' for nil:NilClass when deploying on Heroku - ruby-on-rails

Question

this problem happens when trying to deploy on heroku, I figured it could be the master.key, I redid the project from scratch and the same error occurred. I'm a JS dev, and I'm studying hard to learn RoR.
thanks
I minimize the code error
rails aborted!
NoMethodError: undefined method `[]' for nil:NilClass
/app/config/environments/production.rb:124:in `block in <main>'
...
`perform'
/app/vendor/bundle/ruby/3.0.0/gems/railties-6.1.5/lib/rails/command.rb:50:in `invoke'
/app/vendor/bundle/ruby/3.0.0/gems/railties-6.1.5/lib/rails/commands.rb:18:in `<main>'
/app/vendor/bundle/ruby/3.0.0/gems/bootsnap-1.11.1/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:30:in `require'
/app/vendor/bundle/ruby/3.0.0/gems/bootsnap-1.11.1/lib/bootsnap/load_path_cache/core_ext/kernel_require.rb:30:in `require'
Tasks: TOP => db:migrate => db:load_config => environment
(See full trace by running task with --trace)
I refactor all. try a new repository, master.key new .
this is my production.rb
require 'active_support/core_ext/integer/time'
# rubocop: disable Metrics/BlockLength
Rails.application.configure do
config.cache_classes = true
config.eager_load = true
# Full error reports are disabled and caching is turned on.
config.consider_all_requests_local = false
config.public_file_server.enabled = ENV['RAILS_SERVE_STATIC_FILES'].present?
config.active_storage.service = :local
config.log_level = :info
# Prepend all log lines with the following tags.
config.log_tags = [:request_id]
config.action_mailer.perform_caching = false
config.i18n.fallbacks = true
# Send deprecation notices to registered listeners.
config.active_support.deprecation = :notify
# Log disallowed deprecations.
config.active_support.disallowed_deprecation = :log
# Tell Active Support which deprecation messages to disallow.
config.active_support.disallowed_deprecation_warnings = []
config.log_formatter = ::Logger::Formatter.new
if ENV['RAILS_LOG_TO_STDOUT'].present?
logger = ActiveSupport::Logger.new(STDOUT)
logger.formatter = config.log_formatter
config.logger = ActiveSupport::TaggedLogging.new(logger)
end
config.active_record.dump_schema_after_migration = false
# Email
config.action_mailer.default_url_options = {
host: 'https://max-api-on-rails.herokuapp.com/'
}
config.action_mailer.delivery_method = :smtp
config.action_mailer.smtp_settings = {
address: "smtp.gmail.com",
port: 587,
domain:'gmail.com',
user_name: Rails.application.credentials.zoho[:user_name],
password: Rails.application.credentials.zoho[:password],
authentication: 'login',
ssl: true,
tls: true,
enable_starttls_auto: true
}
end

Answer 1

Error is email smtp configuration. i using zoho, but my credentials is gmail.