Ruby on Rails: Operation now in progress - connect(2) would block

Question

I'm working on a site someone else made. There is a production version.

I'm trying to send emails to users whose properties haven't been updated in 30 days.

Everything works until I try to use deliver_later. The reason I'm using deliver_later is because deliver_now results in an issue of sending too many emails per second. I'm currently using Mailtrap for testing, but I assume I will run into that sort of issue on production.

So I opted to wait 1 second for each email:

      @testproperties = Property.has_not_updated.includes(:user)
      @testproperties.each do |property|
          UserMailer.with(property: property, user: property.user).check_listing.deliver_later(wait:1.seconds)
      end

This results in IO::EINPROGRESSWaitWritable Operation now in progress - connect(2) would block

And nothing sends.

I'm not sure how to solve this issue.

Edit: I can see on the production site that I can visit the route /sidekiq. The routes file has this block:

  authenticate :user, lambda { |u| u.admin? } do
    mount Sidekiq::Web => '/sidekiq'
  end

I can view the web interface and see all the jobs. It's all working there. But I need to access development version running on localhost:3000.

Trying to access this locally still results in:

Operation now in progress - connect(2) would block

  #  # Socket#connect
  def connect_nonblock(addr, exception: true)
    __connect_nonblock(addr, exception)
  end
end

Sidekiq.rb:

require 'sidekiq'

unless Rails.env.test?
  host = 'localhost'
  port = '6379'
  namespace = 'sitename'

  Sidekiq.configure_server do |config|
    config.redis = { url: "redis://#{host}:#{port}", namespace: namespace }
    schedule_file = "config/schedule.yml"
    if File.exists?(schedule_file)
      Sidekiq::Cron::Job.load_from_hash YAML.load_file(schedule_file)
    end
    config.server_middleware do |chain|
      chain.add Sidekiq::Status::ServerMiddleware, expiration: 30.minutes
    end
    config.client_middleware do |chain|
      chain.add Sidekiq::Status::ClientMiddleware, expiration: 30.minutes
    end
  end

  Sidekiq.configure_client do |config|
    config.redis = { url: "redis://#{host}:#{port}", namespace: namespace }
    config.client_middleware do |chain|
      chain.add Sidekiq::Status::ClientMiddleware, expiration: 30.minutes
    end
  end
end

for cable.yml:

development:
  adapter: async
  url: redis://localhost:6379/1
  channel_prefix: sitename_dev

test:
  adapter: async

production:
  adapter: redis
  url: redis://localhost:6379/1
  channel_prefix: sitename_production

Answer 1

The production server is running Ubuntu and they already installed redis-server.

I had not installed that locally. (I'm using Ubuntu through Windows WSL)

sudo apt install redis-server

I can now access the web interface.