Redis redirects to localhost on Heroku (Rails 6)

I have an app hosted on Heroku, using Redis Cloud and ActionCable. Locally everything works but on Heroku the user is redirected to a localhost address after a form is submitted. I have tried most of the advice listed here (apart from resque settings since resque gem is not installed): Redis tries to connect to localhost on Heroku instead of REDIS_URL

Redis Cloud was added with

heroku addons:create rediscloud:30

This is in my cable.yml, I have commented out two other solutions that I tried that also did not work (in my actual code, redis url is set to the actual address rather than xxx999)

production:  adapter: redis  # url: <%= ENV.fetch('REDISCLOUD_URL') %>  # url: <%= ENV.fetch("REDISCLOUD_URL") { "redis://localhost:6379/1" } %>  url: <%= ENV.fetch("REDISCLOUD_URL") { "redis://default:xxx999@redis-13674.c77.eu-west-1-1.ec2.cloud.redislabs.com:13674" } %>  channel_prefix: art--collabs_production

In redis.rb:

if ENV["REDISCLOUD_URL"]  $redis = Redis.new(url: ENV["REDISCLOUD_URL"])end

In production.rb I have the following (again, the commented out code has been tried and also failed)

config.action_cable.url = "ws://www.artcollabs.net/cable"config.action_cable.allowed_request_origins = [ "http://www.artcollabs.net", "https://www.artcollabs.net" ]# config.cache_store = :redis_cache_store, { url: ENV.fetch("REDISCLOUD_URL", "redis://localhost:6379/1") }config.cache_store = :redis_cache_store, { url: ENV.fetch("REDISCLOUD_URL", "redis://default:xxx999@redis-13674.c77.eu-west-1-1.ec2.cloud.redislabs.com:13674") }

Any suggestions on how to solve this?