require the action_cable engine instead of just the root

config/application.rb

@@ -5,7 +5,7 @@ require 'rails'
 #require 'active_record/railtie'
 require 'action_controller/railtie'
 require 'action_mailer/railtie'
-require 'action_cable'
+require 'action_cable/engine'
 #require 'active_resource/railtie'
 require 'rails/test_unit/railtie'
 require 'sprockets/railtie'

config/environments/development.rb

@@ -14,6 +14,8 @@ Mozo::Application.configure do
       resource '*', headers: :any, methods: %i[get post put patch delete options]
     end
   end
+  #config.action_cable.allowed_request_origins = ['https://localhost:4201', 'https://localhost:4202']
+
   config.lnd_credentials_path = '/mnt/ext1/.lnd/tls.cert'
   config.lnd_macaroon_path    = '/mnt/ext1/.lnd/data/chain/bitcoin/mainnet/admin.macaroon'