How to configure Redis/ActionCable on Nginx/Puma server ?

My droplet : Ruby on Rails 6.0.3.4 on Ubuntu 20.04 | Nginx | Puma | SSL

I’m totally new to ActionCable, and trying to set up Actioncable on my Rails application.

My config/cable.yml :

development:
  adapter: redis
  url: redis://localhost:6379

My config/environments/development.rb : i’ve just added this lines

config.action_cable.allowed_request_origins = ["https://my.url.com/"]
config.action_cable.url = "ws://localhost:3000/cable"

Of course: my.url.com is my domain.

My Nginx

upstream websocket {
     server 127.0.0.1:6379;
}

server {

  ....


  location /cable {
    proxy_pass https://websocket/;
    proxy_http_version 1.1;
    proxy_set_header Upgrade $http_upgrade;
    proxy_set_header Connection "Upgrade";

    proxy_set_header X-Forwarded-For $proxy_add_x_forwarded_for;
    proxy_set_header Host $http_host;
    proxy_set_header X-Real-IP $remote_addr;
    proxy_set_header X-Forwarded-Proto https;
    proxy_redirect off;
  }
}

I’m getting this error :

WebSocket connection to 'wss://my.url.com/cable' failed: WebSocket is closed before the connection is established.

Does anyone have a idea ?

Thanks a lot :-)