"Host not permitted" - Opening a Custom App

iliketocode2 · December 8, 2025, 7:51pm

I recently cloned an app into my SandBox Apps and installed all required gems and dependencies. Everything appears to be in the correct location. However, when I launch the app from my SandBox Apps, the page redirects but displays a “Host not permitted” error (403 forbidden).

What’s odd is that my coworkers cloning from the same repository do not encounter this issue. I initially suspected an account permissions or resource limit problem, but reviewing limits.conf didn’t reveal anything relevant. I’ve also tried clearing the cache and restarting the web server, but no luck so far.

Has anyone ever experienced a similar issue or have suggestions for what else I can check? Thanks!

jeff.ohrstrom · December 8, 2025, 8:13pm

Must be a Rails application. You can google “rails host not permitted” and get lots of hits for the same.

You can see how we do this for development

github.com/OSC/ondemand

apps/dashboard/config/environments/development.rb

64e6469ad


      
            config.assets.quiet = true
          
            # Raises error for missing translations.
            config.i18n.raise_on_missing_translations = true
          
            # Annotate rendered view with file names.
            config.action_view.annotate_rendered_view_with_filenames = true
          
            config.active_job.queue_adapter = ActiveJob::QueueAdapters::AsyncAdapter.new(min_threads: 1, max_threads: 1)
          
            config.hosts = nil
          end

and production

github.com/OSC/ondemand

apps/dashboard/config/environments/production.rb

64e6469ad


      
            config.log_formatter = ::Logger::Formatter.new
          
            if ENV['RAILS_LOG_TO_STDOUT'].present?
              logger           = ActiveSupport::Logger.new(STDOUT)
              logger.formatter = config.log_formatter
              config.logger    = ActiveSupport::TaggedLogging.new(logger)
            end
          
            config.active_job.queue_adapter = ActiveJob::QueueAdapters::AsyncAdapter.new(min_threads: 1, max_threads: 1)
          
            config.hosts = ENV['ALLOWED_HOSTS'].nil? ? nil : ENV['ALLOWED_HOSTS'].split(',')
          end

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"Host not permitted" - Opening a Custom App

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