Redmine

Hi,

We're having a bit of a problem with our redmine installation. Occasional Redmine stops working and only return Page not found. Restart works and then it seems to run fine for days or weeks, but sometimes (when most inconvenient, of course) it appears again and Redmine must be restarted.

From what I've found it usually outputs this in the log.

Started GET "/apple-touch-icon-precomposed.png" for 192.168.1.3 at 2017-02-16 07:55:05 +0100

This is then followed by the following log message (with some variation) until the server is restarted.

ActionController::RoutingError (No route matches [GET] "/redmine/product_backlog/5"):
       actionpack (4.2.7.1) lib/action_dispatch/middleware/debug_exceptions.rb:21:in `call'
       actionpack (4.2.7.1) lib/action_dispatch/middleware/show_exceptions.rb:30:in `call'
       railties (4.2.7.1) lib/rails/rack/logger.rb:38:in `call_app'
       railties (4.2.7.1) lib/rails/rack/logger.rb:20:in `block in call'
       activesupport (4.2.7.1) lib/active_support/tagged_logging.rb:68:in `block in tagged'
       activesupport (4.2.7.1) lib/active_support/tagged_logging.rb:26:in `tagged'
       activesupport (4.2.7.1) lib/active_support/tagged_logging.rb:68:in `tagged'
       railties (4.2.7.1) lib/rails/rack/logger.rb:20:in `call'
       actionpack (4.2.7.1) lib/action_dispatch/middleware/request_id.rb:21:in `call'
       rack (1.6.5) lib/rack/methodoverride.rb:22:in `call'
       rack (1.6.5) lib/rack/runtime.rb:18:in `call'
       activesupport (4.2.7.1) lib/active_support/cache/strategy/local_cache_middleware.rb:28:in `call'
       actionpack (4.2.7.1) lib/action_dispatch/middleware/static.rb:120:in `call'
       rack (1.6.5) lib/rack/content_length.rb:15:in `call'
       rack (1.6.5) lib/rack/sendfile.rb:113:in `call'
       railties (4.2.7.1) lib/rails/engine.rb:518:in `call'
       railties (4.2.7.1) lib/rails/application.rb:165:in `call'
       railties (4.2.7.1) lib/rails/railtie.rb:194:in `public_send'
       railties (4.2.7.1) lib/rails/railtie.rb:194:in `method_missing'
       passenger (5.0.30) src/ruby_supportlib/phusion_passenger/rack/thread_handler_extension.rb:97:in `process_request'
       passenger (5.0.30) src/ruby_supportlib/phusion_passenger/request_handler/thread_handler.rb:152:in `accept_and_process_next_request'
       passenger (5.0.30) src/ruby_supportlib/phusion_passenger/request_handler/thread_handler.rb:113:in `main_loop'
       passenger (5.0.30) src/ruby_supportlib/phusion_passenger/request_handler.rb:416:in `block (3 levels) in start_threads'
       passenger (5.0.30) src/ruby_supportlib/phusion_passenger/utils.rb:113:in `block in create_thread_and_abort_on_exception'

Regarding the apple-touch-icon-precomposed.png - this is triggered by iOS devices. Could this interfere with Redmine?
I don't have a way to reproduce the issue, unfortunately.

Any ideas on why this is happening? Attaching server details below.

Environment:
      Redmine version                3.3.2.stable.16326
      Ruby version                   2.3.1-p112 (2016-04-26) [x86_64-linux-gnu]
      Rails version                  4.2.7.1
      Environment                    production
      Database adapter               PostgreSQL
    SCM:
      Subversion                     1.9.3
      Mercurial                      3.7.3
      Git                            2.7.4
      Filesystem                     
    Redmine plugins:
      redmine_checklists             3.1.5
      redmine_embedded               0.0.2
      redmine_mylyn_connector        2.8.2.stable
      redmine_wiki_extensions        0.7.0
      scrum                          0.16.2

Thanks in advance!