If you're using Unicorn, you have to fill in the number you've defined in worker_processes from your app/config/unicorn.rb file. Number of connections per Web dyno, (per Unicorn worker) minimum 1. Only change this value if you query the Redis database more than just for adding tasks to the Sidekiq queue. # app/config/initializers/sidekiq.rb require 'sidekiq' Sidekiq.configure_client do |config| co