Krzysztof Pietrzyk

Your solution worked for me - on Linux Ubuntu - Thank you :)

Linux / Ubuntu 20
If anyone has a problem when everything is started: Redis-> Sidekiq -> Rails Server and Sidekiq is doing nothing - no changes in the console - no posted tweet.

Create a file in config/initializers/sidekiq.rb
Copy/Paste inside and save:

Sidekiq.configure_server do |config|
  config.redis = { url: 'redis://localhost:6379/0' }
end

Sidekiq.configure_client do |config|
  config.redis = { url: 'redis://localhost:6379/0' }

Restart everything and run again.

Let me know if it does work for you.