Rails Redis Cache Configuration

environment.rb

# For TLS Connections
  config.cache_store = :redis_cache_store, {
    url: ENV.fetch('CACHE_STORE_REDIS_TLS_URL') { ENV['CACHE_STORE_REDIS_URL'] || 'redis://127.0.0.1:6379' },
    db: 0,
    connect_timeout: 20,  # Defaults to 20 seconds
    read_timeout: 1, # Defaults to 1 second
    write_timeout: 1, # Defaults to 1 second
    reconnect_delay: 1.5 ,
    reconnect_delay_max: 10.0,
    reconnect_attempts: 10,   # Defaults to 0
    ssl_params: { verify_mode: OpenSSL::SSL::VERIFY_NONE },
    expires_in: 12.hours,
  }

ssl_params: { verify_mode: OpenSSL::SSL::VERIFY_NONE },
this line specifically fixed my issue on heroku.